Ventricular assist device

Abstract

This application relates to ventricular assist devices. An apparatus and method comprising a left ventricular assist device (20) are described, the left ventricular assist device including a tube (24) configured to pass through the aortic valve of a subject, the distal portion of which is disposed within the left ventricle of the subject. A frame (34) is disposed within the distal portion of the tube. A pump (50) disposed within the frame pumps blood through the tube. A distal tip element (107) defines a straight proximal portion (346) and a curved distal portion, the straight proximal portion defining a longitudinal axis (348), the curved distal portion being shaped to bend in a first direction relative to the longitudinal axis (348) before passing an inflection point and bending in a second direction relative to the longitudinal axis (348), such that the curved distal portion defines a bulge (351) on one side of the longitudinal axis (348). Other applications are also described.

Description

[0001] This application is a divisional application of the application filed on January 23, 2020, with application number 202080017728.9 and invention title "Ventricular Assist Device".

[0002] Cross-references to related applications

[0003] This application claims priority for the following items:

[0004] Tuval filed U.S. provisional patent application 62 / 796,138 entitled “Ventricular assist device” on January 24, 2019;

[0005] Tuval filed U.S. Provisional Patent Application No. 62 / 851,716 on May 23, 2019, entitled “Ventricular assist device”.

[0006] Tuval's U.S. Provisional Patent Application No. 62 / 870,821, entitled "Ventricular assist device," filed July 5, 2019; and

[0007] Tuval filed U.S. Provisional Patent Application No. 62 / 896,026 on September 5, 2019, entitled “Ventricular assist device”.

[0008] This application relates to a U.S. application filed on the same date as this application entitled “Distal tip element for a ventricular assist device”, which claims priority to the aforementioned U.S. provisional application.

[0009] All of the above-cited applications are incorporated herein by reference.

[0010] Field of the Invention

[0011] Some applications of this invention generally relate to medical devices. Specifically, some applications of this invention relate to ventricular assist devices and methods of using them. background

[0012] Ventricular assist devices are mechanical circulatory support devices designed to assist and unload the heart chambers to maintain or increase cardiac output. These devices are used in patients with heart failure and those at risk of cardiac function deterioration during percutaneous coronary intervention. Most commonly, left ventricular assist devices are administered to defective hearts to assist left ventricular function. In some cases, right ventricular assist devices are used to assist right ventricular function. These devices may be designed for permanent implantation or placed temporarily via a catheter.

[0013] Implementation Examples Overview

[0014] According to some applications of the invention, a ventricular assist device includes an impeller disposed on an axial shaft, with a frame disposed around the impeller. Typically, the ventricular assist device includes a tube passing through the aortic valve of a subject, such that the proximal end of the tube is positioned within the subject's aorta, and the distal end of the tube is positioned within the subject's left ventricle. The impeller, axial shaft, and frame are disposed within the distal portion of the tube located within the subject's left ventricle. Typically, the impeller is configured to pump blood from the left ventricle into the aorta by rotation. Typically, the tube defines one or more blood inlet openings at its distal end, through which blood flows from the left ventricle into the tube during impeller operation. For some applications, the proximal portion of the tube defines one or more blood outlet openings, through which blood flows from the tube into the ascending aorta during impeller operation.

[0015] For some applications, ventricular assist devices include a distal tip element configured to define a flat proximal portion and a curved distal portion. The flat proximal portion defines a longitudinal axis, and the curved distal portion is shaped to bend in a first direction relative to the longitudinal axis of the flat proximal portion before bending in a second direction relative to the longitudinal axis of the flat proximal portion at an inflection point, such that the curved distal portion defines a bulge on one side of the longitudinal axis of the flat proximal portion. Typically, the distal tip element has a question mark shape and / or a tennis racket shape.

[0016] In some applications, the distal tip element is configured to separate the blood inlet opening from the posterior wall of the subject's left ventricle when the distal tip element is placed against the apex of the subject's left ventricle. Typically, the distal tip element is configured to separate the blood inlet opening from the septal wall of the subject's left ventricle when the distal tip element contacts the apex of the subject's left ventricle. More typically, the distal tip element is configured such that when the distal tip element is inserted into the left ventricle such that the bulge bulges towards the septal wall, in response to the distal tip element being pushed against the apex of the subject's left ventricle, the blood inlet opening is pushed away from the septal wall and towards the free wall of the subject's left ventricle. In some applications, the blood inlet opening is pushed away from the septal wall and towards the free wall of the subject's left ventricle by pivoting the straight proximal portion of the distal tip element about the curved distal portion of the distal tip element.

[0017] For some applications, the duckbill valve is positioned within 10 mm of the distal tip element. Typically, the duckbill valve defines a wide inlet and a narrow tip, the narrow tip defining a slit therethrough. The duckbill valve faces proximally such that the wide inlet faces the distal end of the distal tip element, and the narrow tip faces away from the distal end of the distal tip element. For some applications, the ventricular assist device is configured for use with a lead wire, and the distal tip element defines a lead wire lumen. For some such applications, the ventricular assist device also includes a lead wire guide positioned within the lead wire lumen proximally to the duckbill valve. Typically, the lead wire guide is shaped to define a through-hole, the diameter of which narrows from the proximal end to the distal end of the lead wire guide. The shape of the lead wire guide is configured to guide the tip of the lead wire toward the slit at the narrow proximal end of the duckbill valve when the lead wire is inserted from the proximal end of the left ventricular assist device. For some applications, the duckbill valve is shaped to define a converging guide portion at its proximal end, which converges toward the gap, such that the guide portion is configured to further guide the tip of the guide wire toward the gap.

[0018] Typically, a frame surrounding the impeller defines multiple cells, and the frame is configured such that, in a non-radially constrained configuration, the frame comprises a generally cylindrical portion. More typically, the width of each cell within the cylindrical portion, measured around the circumference of the cylindrical portion, is less than 2 mm (e.g., 1.4 mm–1.6 mm, or 1.6 mm–1.8 mm). For some applications, a liner is at least lining the cylindrical portion of the frame, and the impeller is positioned within the frame such that, in a non-radially constrained configuration, at the location of the impeller's greatest span, the impeller is positioned within the cylindrical portion of the frame, such that the gap between the outer edge of the impeller and the liner is less than 1 mm (e.g., less than 0.4 mm). Typically, the impeller is configured to rotate to pump blood from the left ventricle to the aorta and is configured to be stable relative to the frame such that, during impeller rotation, the gap between the outer edge of the impeller and the liner is maintained and substantially constant. For some applications, the impeller is configured to reduce the risk of hemolysis by being stable relative to the frame, compared to a case where the impeller is unstable relative to the frame.

[0019] For some applications, proximal and distal radial supports are positioned at the proximal and distal ends of the frame, respectively, and an axial shaft passes through both supports. Typically, the impeller is stabilized relative to the frame by holding it in a radially fixed position relative to the axial shaft, and by the rigidity of the axial shaft. For some applications, the impeller includes bushings disposed around the axial shaft, and at least one of these bushings is configured to be slidable relative to the axial shaft. For some applications, the impeller is stabilized relative to the frame by a region along the axial shaft in which at least one bushing is configured to be slidable relative to the axial shaft, and this region is coated to substantially prevent impeller vibration by reducing the clearance between at least one bushing and the impeller. For example, this region may be coated with a diamond-like carbon coating, a polytetrafluoroethylene coating, and / or a polymer sleeve.

[0020] For some applications, the frame defines struts that are structured such that as the frame transitions from its proximal end to its center, the struts pass through a joint where pairs of struts branch off from a single strut in a Y-shape. Typically, the struts of the frame are structured such that, in response to the distal end of the delivery conduit and the frame being moved to a position relative to each other (e.g., by advancing the distal end of the delivery conduit onto the frame, or by retracting the frame into the distal end of the delivery conduit), the frame is configured to exhibit its radially constrained configuration by becoming axially elongated, and is configured such that the impeller exhibits its radially constrained configuration by becoming axially elongated (e.g., by the pairs of struts branching off from each joint being configured to pivot about the joint and move closer to each other, thereby closing in response to the distal end of the delivery conduit and the frame being moved to a position relative to each other).

[0021] For some applications, the housing of the impeller for a blood pump is manufactured by performing the following steps: A liner is placed around a mandrel. A cylindrical portion of a frame, including struts defining a generally cylindrical shape, is placed around the liner. A distal portion of an elongated tube, including a proximal portion defining at least one blood outlet opening, is placed around at least a portion of the frame. While the distal portion is positioned around at least a portion of the frame, the liner, frame, and distal portion of the elongated tube are heated via the mandrel. While heating the liner, frame, and distal portion of the elongated tube, pressure is applied from outside the distal portion of the elongated tube to conform the structure of the elongated tube to the struts of the frame and to connect the liner and the distal portion of the elongated tube to the frame. For example, pressure can be applied by a silicone tube placed outside the distal portion of the elongated tube. For some applications, the liner and the elongated tube comprise liner and elongated tube made of different materials from each other, and the thermoforming temperature of the material manufacturing the liner is higher than the thermoforming temperature of the material manufacturing the elongated tube. For some such applications, the liner, frame, and distal portion of the elongated tube are heated to temperatures higher than the thermoforming temperature of the material used to manufacture the elongated tube and lower than the thermoforming temperature of the material used to manufacture the liner.

[0022] For some applications, the impeller is manufactured as follows: a structure is formed having a first bushing and a second bushing at its proximal and distal ends, the first and second bushings being connected to each other by at least one elongated element. The structure is at least partially compressed axially, causing the at least one elongated element to expand radially and form at least one helical elongated element. An elastomeric material is coupled to the at least one helical elongated element such that the at least one helical elongated element with the coupled elastomeric material defines the blades of the impeller. Typically, the coupling is performed such that a layer of material is disposed around the radially outer edge of the at least one helical elongated element, the layer of material forming the effective edge of the impeller blades (i.e., the edge where the impeller's blood pumping function is essentially no longer effective). More typically, the method includes performing the step of reinforcing the bond between the elastomeric material and the at least one helical elongated element in a manner that does not cause protrusion from the effective edge of the impeller blades. For example, a suture can be placed within a groove defined by the at least one helical elongated element such that the suture does not protrude from the radially outer edge of the helical elongated element, the suture being configured to reinforce the bond between the elastomeric material and the at least one helical elongated element. Alternatively or additionally, a tightly wound coil is placed around at least one helical elongated element, such that the elastomeric material forms a substantially smooth layer along the radially outer edge of the coil, the coil being configured to reinforce the bonding between the elastomeric material and the at least one helical elongated element. Further alternatively or additionally, a sleeve is placed around at least one helical elongated element, such that the elastomeric material forms a substantially smooth layer along the radially outer edge of the sleeve, the sleeve being configured to reinforce the bonding between the elastomeric material and the at least one helical elongated element. For some applications, a rounded cross-section is provided for the at least one helical elongated element, such that the elastomeric material forms a substantially uniform layer at the interface between the elastomeric material and the helical elongated element.

[0023] Generally, in the specification and claims of this application, when used with respect to a device or a portion thereof, the term "proximal" and related terms should be interpreted as meaning that, when the device or a portion thereof is inserted into a subject's body, the end of the device or a portion thereof is generally closer to the location through which the device is inserted into the subject's body. When used with respect to a device or a portion thereof, the term "distal" and related terms should be interpreted as meaning that, when the device or a portion thereof is inserted into a subject's body, the end of the device or a portion thereof is generally farther from the location through which the device is inserted into the subject's body.

[0024] The scope of this invention includes the use of the instruments and methods described herein in anatomical locations other than the left ventricle and aorta. Therefore, ventricular assist devices and / or portions thereof are sometimes referred to herein (in the specification and claims) as blood pumps.

[0025] Therefore, according to some applications of the present invention, an apparatus is provided, comprising:

[0026] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0027] The tube is configured such that the proximal portion of the tube passes through the subject's aortic valve, and the distal portion of the tube is positioned in the subject's left ventricle.

[0028] A frame, which is disposed within at least the distal portion of the tube;

[0029] A pump, disposed within a frame and configured to pump blood from the left ventricle of a subject to the subject's aorta via a tube, wherein blood is pumped into the tube via at least one blood inlet opening defined by the tube and configured to be located within the subject's left ventricle, and blood is pumped out of the tube via at least one blood outlet opening defined by the tube and configured to be located within the subject's aorta; and

[0030] A distal tip element is configured to define a flat proximal portion and a curved distal portion, the flat proximal portion defining a longitudinal axis, the curved distal portion being shaped to bend in a first direction relative to the longitudinal axis of the flat proximal portion before bending in a second direction relative to the longitudinal axis of the flat proximal portion at an inflection point, such that the curved distal portion defines a bulge on one side of the longitudinal axis of the flat proximal portion.

[0031] For some applications, the distal tip element is configured to separate at least one blood inlet opening from the posterior wall of the subject's left ventricle when the distal tip element is placed against the apex of the subject's left ventricle.

[0032] For some applications, the distal tip element has a question mark shape. For some applications, the distal tip element has a tennis racket shape.

[0033] For some applications, the curved distal portion of the distal tip element is shaped such that after passing the inflection point, the curved distal portion continues to curve, causing the curved distal portion to cross back onto the longitudinal axis defined by the straight proximal portion. For some applications, the curved distal portion of the distal tip element is shaped such that after passing the inflection point, the curved distal portion does not cross back onto the longitudinal axis defined by the straight proximal portion.

[0034] For some applications, the blood pump includes an impeller disposed on an axial shaft, and the distal tip element includes an axial shaft receiving tube configured to receive the axial shaft of the blood pump, and a distal tip portion configured to define a curved distal portion of the distal tip element.

[0035] In some applications, the distal tip element is configured to separate at least one blood inlet opening from the septal wall of the subject's left ventricle when the distal tip element contacts the apex of the subject's left ventricle. In some applications, the distal tip element is configured such that when the distal tip element is inserted into the left ventricle such that the bulge bulges towards the septal wall, in response to the distal tip element being pushed against the apex of the subject's left ventricle, the blood inlet opening is pushed away from the septal wall and towards the free wall of the subject's left ventricle. In some applications, the distal tip element is configured such that in response to the distal tip element being pushed against the apex of the subject's left ventricle, the blood inlet opening is pushed away from the septal wall and towards the free wall of the subject's left ventricle by pivoting the straight proximal portion of the distal tip element about the curved distal portion of the distal tip element.

[0036] For some applications, the distal tip element is configured such that, when deployed within the descending aorta of a subject, the distal tip element itself is centered relative to the subject's aortic valve. For some applications, the curved distal portion is shaped to define an elongated straight portion after bending in a first direction and before bending in a second direction, such that the elongated straight portion protrudes at an angle relative to the longitudinal axis of the proximal straight portion of the distal tip element.

[0037] For some applications, the duckbill valve is positioned within 10 mm of the farthest end of the distal tip element. For some applications, the duckbill valve defines a wide inlet and a narrow tip, the narrow tip defining a slit through which it passes, with the duckbill valve facing proximally such that the wide inlet faces the distal end of the distal tip element and the narrow tip faces away from the distal end of the distal tip element.

[0038] For some applications:

[0039] The left ventricular assist device is configured for use with a guide wire;

[0040] The distal tip element defines the guide wire lumen; and

[0041] The left ventricular assist device also includes a lead wire guide disposed within the lumen of the lead wire proximal to the duckbill valve. The lead wire guide is shaped to define an aperture therethrough, the diameter of which narrows from the proximal end of the lead wire guide to the distal end of the lead wire guide. The shape of the lead wire guide is configured to guide the tip of the lead wire toward a slit at the narrow proximal end of the duckbill valve when the lead wire is inserted from the proximal end of the left ventricular assist device.

[0042] For some applications, the duckbill valve is shaped to define a converging guide portion at its proximal end, which converges toward the gap, such that the guide portion is configured to further guide the tip of the guide wire toward the gap.

[0043] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0044] A blood pump, configured to be placed inside a subject, comprises:

[0045] impeller;

[0046] The frame is configured to be arranged around the impeller;

[0047] The distal tip portion, which is positioned distally relative to the frame; and

[0048] The duckbill valve is positioned entirely within 10mm of the farthest point of the distal tip.

[0049] The duckbill valve defines a wide inlet and a narrow tip, the narrow tip defining a slit that passes through it.

[0050] The duckbill valve faces proximally, such that the wide inlet faces the distal end of the distal tip portion, and the narrow tip faces away from the distal end of the distal tip portion.

[0051] According to some applications of the present invention, an apparatus for use with a guide wire is also provided, the apparatus comprising:

[0052] A percutaneous medical device that defines a guideline lumen extending from the proximal end of the device to the distal end of the device;

[0053] The duckbill valve is located in the distal portion of the guide wire's inner cavity.

[0054] The duckbill valve defines a wide inlet and a narrow tip, the narrow tip defining a slit that passes through it.

[0055] The duckbill valve faces proximally, such that the wide inlet face is directed toward the distal end of the guide wire lumen, and the narrow tip is directed away from the distal end of the guide wire lumen; and

[0056] A wire guide is disposed within the inner cavity of the wire proximal to the duckbill valve. The wire guide is shaped to define a hole therethrough, the diameter of which narrows from the proximal end of the wire guide to the distal end of the wire guide. The shape of the wire guide is configured to guide the tip of the wire toward a slit at the narrow proximal end of the duckbill valve when the wire is inserted from the proximal end of the percutaneous medical device.

[0057] For some applications, the duckbill valve is shaped to define a converging guide portion at its proximal end, which converges toward the gap, such that the guide portion is configured to further guide the tip of the guide wire toward the gap.

[0058] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0059] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0060] A tube, configured to pass through the subject's aortic valve, such that the proximal end of the tube is placed within the subject's aorta and the distal end of the tube is placed within the subject's left ventricle.

[0061] A frame, which is disposed within at least a portion of a tube, defines a plurality of cells, and is configured such that, in a non-radial constraint configuration of the frame, the frame includes a generally cylindrical portion, wherein the width of each cell within the cylindrical portion, measured around the circumference of the cylindrical portion, is less than 2 mm.

[0062] The lining, which is placed over at least a portion of the columnar portion of the frame; and

[0063] The impeller is positioned within the frame, such that in the non-radial constrained configuration of the impeller, at the position of maximum impeller span, the impeller is located within the cylindrical portion of the frame, ensuring that the gap between the outer edge of the impeller and the inner liner is less than 1 mm.

[0064] The impeller is configured as follows:

[0065] Rotation allows blood to be pumped from the left ventricle to the aorta, and

[0066] The frame is stable, which allows the gap between the outer edge of the impeller and the inner liner to be maintained and remain essentially constant during impeller rotation.

[0067] For some applications, the impeller is configured to reduce the risk of hemolysis by being stable relative to the frame, compared to cases where the impeller is unstable relative to the frame.

[0068] For some applications, the width of each cell within the column portion, measured around the circumference of the column portion, is between 1.4 mm and 1.6 mm.

[0069] For some applications, the width of each cell within the column portion, measured around the circumference of the column portion, is between 1.6 mm and 1.8 mm.

[0070] For some applications, the impeller is configured such that the gap between the outer edge of the impeller and the inner liner is less than 0.4 mm.

[0071] For some applications:

[0072] The left ventricular assist device also includes an axial shaft and a proximal radial support and a distal radial support respectively located at the proximal and distal ends of the frame, with the axial shaft passing through the proximal radial support and the distal radial support;

[0073] The impeller is connected to the axial shaft; and

[0074] The impeller is stabilized relative to the frame by keeping the impeller in a radially fixed position relative to the axial shaft, and the axial shaft is rigid.

[0075] For some applications, the impeller includes bushings arranged around an axial shaft, at least one of which is configured to be slidable relative to the axial shaft, and the impeller is stabilized relative to the frame by a region along the axial shaft in which at least one bushing is configured to be slidable relative to the axial shaft, the region being coated to substantially prevent impeller vibration by reducing the clearance between at least one bushing and the axial shaft.

[0076] For some applications, the impeller is stabilized relative to the frame by ensuring that the ratio of the length of the cylindrical portion of the frame to the total length of the frame is greater than 1:2, which essentially prevents vibration of the frame relative to the axial shaft.

[0077] For some applications, the ratio of the length of the column section of the frame to the total length of the frame is greater than 2:3.

[0078] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0079] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0080] A tube, configured to pass through the subject's aortic valve, such that the proximal end of the tube is placed within the subject's aorta and the distal end of the tube is placed within the subject's left ventricle.

[0081] A frame, which is disposed within at least a portion of a tube, defines a plurality of cells, and is configured such that, in a non-radial constraint configuration of the frame, the frame includes a generally cylindrical portion;

[0082] The proximal radial support and the distal radial support are respectively located at the proximal end and the distal end of the frame;

[0083] An axial shaft passes through the proximal radial support and the distal radial support;

[0084] The lining, which is placed over at least a portion of the columnar portion of the frame; and

[0085] The impeller, connected to an axial shaft within the frame, is positioned within the cylindrical section of the frame at the point of maximum impeller span in a non-radial constrained configuration. This ensures that the gap between the outer edge of the impeller and the inner liner is less than 1 mm.

[0086] The impeller includes bushings disposed around the axial shaft, at least one of which is configured to be slidable relative to the axial shaft, and

[0087] The impeller is stabilized relative to the frame by the following region along the axial shaft, in which at least one bushing is configured to be slidable relative to the axial shaft, and this region is coated to substantially prevent impeller vibration by reducing the clearance between at least one bushing and the impeller.

[0088] For some applications, at least one bushing is configured to be slidable relative to the axial shaft in a region along the axial shaft, and this region is coated with a diamond-like carbon coating. For some applications, at least one bushing is configured to be slidable relative to the axial shaft in a region along the axial shaft, and this region is coated with a polytetrafluoroethylene coating. For some applications, at least one bushing is configured to be slidable relative to the axial shaft in a region along the axial shaft, and this region is coated with a polymer sleeve. For some applications, the impeller is configured to reduce the risk of hemolysis by being stabilized relative to the frame, compared to a case where the impeller is unstable relative to the frame.

[0089] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0090] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0091] A tube, configured to pass through the subject's aortic valve, such that the proximal end of the tube is placed within the subject's aorta and the distal end of the tube is placed within the subject's left ventricle.

[0092] A frame, which is disposed within at least a portion of a tube, defines a plurality of cells, and is configured such that, in a non-radial constraint configuration of the frame, the frame includes a generally cylindrical portion;

[0093] The proximal radial support and the distal radial support are respectively located at the proximal end and the distal end of the frame;

[0094] An axial shaft passes through the proximal radial support and the distal radial support;

[0095] The lining, which is placed over at least a portion of the columnar portion of the frame; and

[0096] The impeller, connected to an axial shaft within the frame, is positioned within the cylindrical section of the frame at the point of maximum impeller span in a non-radial constrained configuration. This ensures that the gap between the outer edge of the impeller and the inner liner is less than 1 mm.

[0097] The impeller is stabilized relative to the frame by means that the ratio of the length of the columnar portion of the frame to the total length of the frame is greater than 1:2, which essentially prevents the frame from vibrating relative to the axial shaft.

[0098] For some applications, the ratio of the length of the column section of the frame to the total length of the frame is greater than 2:3.

[0099] For some applications, the impeller is configured to reduce the risk of hemolysis by being stabilized relative to the frame, compared to situations where the impeller is unstable relative to the frame.

[0100] According to some applications of the present invention, a method is also provided, the method comprising:

[0101] The impeller is manufactured as follows:

[0102] A structure is formed having a first bushing and a second bushing at its proximal and distal ends, the first bushing and the second bushing being connected to each other by at least one elongated element.

[0103] At least partially by axially compressing the structure, the at least one elongated element is radially expanded and forms at least one helical elongated element; and

[0104] An elastomeric material is coupled to at least one helical elongated element such that the at least one helical elongated element with the coupled elastomeric material defines the blades of an impeller, and the coupling is performed such that a material layer is disposed around the radial outer edge of the at least one helical elongated element, the material layer forming the effective edge of the blades of the impeller.

[0105] The method includes performing a step of reinforcing the bonding of the elastomeric material with at least one helical elongated element in a manner that does not cause it to protrude from the effective edge of the impeller blades.

[0106] For some applications, manufacturing the impeller also includes: placing a spring within the structure such that the spring extends from a first bushing to a second bushing; and attaching the elastomeric material to at least one helical elongated element includes: forming a film of the elastomeric material extending from at least one helical elongated element to the spring.

[0107] For some applications:

[0108] The structure includes: a structure having a first bushing and a second bushing at the proximal and distal ends of the structure, the end portions being connected to each other by two elongated elements;

[0109] Expanding at least one elongated element radially to form at least one helical elongated element includes: expanding two elongated elements radially to form two helical elongated elements; and

[0110] Connecting an elastomeric material to at least one helical elongated element includes connecting the elastomeric material to two helical elongated elements such that the two helical elongated elements connected with the elastomeric material define the blades of an impeller.

[0111] For some applications:

[0112] The structure includes: a structure having a first bushing and a second bushing at the proximal and distal ends of the structure, the end portions being connected to each other by three or more elongated elements;

[0113] Expanding at least one elongated element radially to form at least one helical elongated element includes: expanding three elongated elements radially to form three or more helical elongated elements; and

[0114] Connecting an elastomeric material to at least one helical elongated element includes connecting the elastomeric material to three or more helical elongated elements such that each of the three or more helical elongated elements connected with the elastomeric material defines a corresponding blade of an impeller.

[0115] For some applications, extending at least one elongated element radially and forming at least one helical elongated element further includes twisting the structure.

[0116] For some applications, the step of bonding the reinforcing elastomer material with at least one helical elongated element includes: placing a suture within a groove defined by at least one helical elongated element such that the suture does not protrude from the radial outer edge of the helical elongated element, the suture being configured for bonding the reinforcing elastomer material with at least one helical elongated element.

[0117] For some applications, the step of performing the bonding of the reinforcing elastomer material with at least one helical elongated element includes: placing a tightly wound coil around the at least one helical elongated element such that the elastomer material forms a substantially smooth layer along the radial outer edge of the coil, the coil being configured to reinforce the bonding of the elastomer material with the at least one helical elongated element.

[0118] For some applications, the step of performing the bonding of the reinforcing elastomer material with at least one helical elongated element includes: placing a sleeve around the at least one helical elongated element such that the elastomer material forms a substantially smooth layer along the radial outer edge of the sleeve, the sleeve being configured to reinforce the bonding of the elastomer material with the at least one helical elongated element.

[0119] For some applications, the step of combining the reinforcing elastomer material with at least one helical elongated element includes: providing a rounded cross section for the at least one helical elongated element such that the elastomer material forms a layer of substantially uniform thickness at the interface between the elastomer material and the helical elongated element.

[0120] According to some applications of the present invention, an instrument for use with a delivery catheter is also provided, the instrument comprising:

[0121] The blood pump includes:

[0122] An impeller, configured to pump blood through the subject's body;

[0123] The frame, which is arranged around the impeller,

[0124] The impeller and frame define a non-radial constraint configuration in which the impeller is configured to pump blood within the subject, and a radial constraint configuration in which the impeller and frame are inserted into and removed from the subject using a delivery catheter.

[0125] The frame defines the struts, which have a structure that, as the frame transitions from the proximal end to the center of the frame, the struts pass through a joint where two struts branch off from a single strut in a Y-shape.

[0126] The structure of the frame's struts is configured such that, in response to the distal end of the delivery duct and the frame being moved to a position relative to each other, the frame is configured to exhibit its radially constrained configuration by becoming axially elongated, and the impeller is configured to exhibit its radially constrained configuration by becoming axially elongated.

[0127] For some applications, the structure of the frame struts is configured such that, in response to the distal end of the delivery duct and the frame being moved to a position relative to each other, the frame is configured to exhibit its radially constrained configuration by becoming axially elongated, and the impeller is configured to exhibit its radially constrained configuration by becoming axially elongated, in such a way that the paired struts extending from the joint are configured to pivot about the joint and move closer to each other, thereby closing.

[0128] For some applications, the frame defines a proximal tapered portion, a distal tapered portion, and a cylindrical portion between the proximal and distal tapered portions in its radially unconstrained configuration.

[0129] For some applications, the support density of the frame is constant within the column section of the frame.

[0130] For some applications, the density of the struts increases from the proximal tapered section to the cylindrical section, and from the distal tapered section to the cylindrical section.

[0131] For some applications, during operation of the blood pump, the impeller is configured to move relative to the frame, and the range of movement of the impeller is such that during at least some operation of the blood pump, at least a portion of the impeller is disposed within the proximal conical portion of the frame, and during at least some operation of the blood pump, at least a portion of the impeller is disposed within the cylindrical portion of the frame.

[0132] For some applications, during the entire operation of the blood pump, at the position where the impeller span is the largest, the impeller is configured to be set within the columnar section of the frame.

[0133] For some applications, the width of each cell within the column portion, measured around the circumference of the column portion, is less than 2 mm.

[0134] For some applications, the width of each cell within the column portion, measured around the circumference of the column portion, is between 1.4 mm and 1.6 mm.

[0135] For some applications, the width of each cell within the column portion, measured around the circumference of the column portion, is between 1.6 mm and 1.8 mm.

[0136] According to some applications of the present invention, a method is also provided, the method comprising:

[0137] The housing for the impeller of the blood pump is manufactured through the following steps:

[0138] Place the inner liner around the mandrel;

[0139] The columnar portion of the frame is placed around the lining, and the columnar portion of the frame includes pillars that define a generally columnar shape.

[0140] A distal portion of an elongated tube is placed around at least a portion of the frame, the tube including a proximal portion that defines at least one blood outlet opening;

[0141] When the distal portion is arranged around at least a portion of the frame, the liner, frame, and distal portion of the elongated tube are heated via a mandrel; and

[0142] When heating the liner, frame, and distal portion of the elongated tube, pressure is applied from the outside of the distal portion of the elongated tube to align the distal portion of the elongated tube with the structure of the frame's supports and to connect the liner and the distal portion of the elongated tube to the frame.

[0143] For some applications, the method further includes shaping the distal end of the frame to define a widened inlet after attaching the liner and the distal portion of the elongated tube to the frame.

[0144] For some applications, the method further includes: after attaching the liner and the distal portion of the elongated tube to the frame, shaping a portion of the frame to form a converging region, such that the frame defines a narrowing region near the location within the frame configured to accommodate the impeller.

[0145] For some applications, placing the distal portion of the elongated tube around at least a portion of the frame includes placing the distal portion of the elongated tube around the entire cylindrical portion of the frame such that the distal portion of the elongated tube overlaps with the entire liner.

[0146] For some applications:

[0147] The liner and the elongated tube comprise a liner and an elongated tube made of different materials from each other, and the thermoforming temperature of the material used to manufacture the liner is higher than the thermoforming temperature of the material used to manufacture the elongated tube.

[0148] Heating the liner, frame, and distal portion of the elongated tube includes heating the liner, frame, and distal portion of the elongated tube to a temperature higher than the thermoforming temperature of the material used to manufacture the elongated tube but lower than the thermoforming temperature of the material used to manufacture the liner.

[0149] For some applications, applying pressure from the outside of the distal portion of the elongated tube includes: applying pressure from the outside of the distal portion of the elongated tube using an outer tube made of silicone.

[0150] For some applications, applying pressure from the outside of the distal portion of the elongated tube to connect the liner and the distal portion of the elongated tube to the frame includes: connecting the liner to the inner surface of the columnar portion of the frame, such that the liner forms a substantially columnar tube.

[0151] For some applications, the supports within the columnar section of the frame are shaped into defined cells, and the width of each cell measured around the circumference of the columnar section is less than 2 mm.

[0152] For some applications, placing the distal portion of the elongated tube around at least a portion of the frame includes placing the distal portion of the elongated tube only around a portion of the columnar portion of the frame, such that the distal portion of the elongated tube does not overlap with the entire liner.

[0153] For some applications, placing the distal portion of the elongated tube only around a portion of the columnar portion of the frame includes: preventing the portion of the columnar portion of the frame surrounded by the distal portion of the elongated tube from radially expanding, thereby causing the portion of the columnar portion of the frame surrounded by the distal portion of the elongated tube to be narrower than the portion of the columnar portion of the frame not surrounded by the distal portion of the elongated tube.

[0154] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0155] A blood pump, configured to be placed inside a subject, comprises:

[0156] impeller;

[0157] A frame configured to be arranged around the impeller, the frame including supports;

[0158] The lining, which is set within the frame;

[0159] The outer covering material connects to the inner connecting material from the outside of the frame at discrete connection areas along the length of the frame.

[0160] Along the length of the frame, the density of the frame's supports in the joint area is less than the density of the frame's supports in other areas.

[0161] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0162] A blood pump, configured to be placed inside a subject, comprises:

[0163] impeller;

[0164] A frame configured to surround the impeller, the frame including struts, and the columnar portion of the frame being shaped to define a columnar cross-section;

[0165] The lining, which is set within the frame;

[0166] An external covering material, which connects from the outside of the frame to the internal connecting material, is disposed only around a portion of the columnar portion of the frame, and is configured to limit the radial expansion of the portion of the columnar portion of the frame around which the external covering material is disposed, such that the distal portion of the columnar region of the frame around which the external covering material is disposed is narrower than the portion of the columnar region of the frame not around which the external covering material is disposed.

[0167] According to some applications of the present invention, an apparatus is also provided, the apparatus comprising:

[0168] A blood pump, configured to be placed inside a subject, comprises:

[0169] impeller;

[0170] A frame, configured to surround the impeller, is configured to define a cylindrical portion having a substantially cylindrical cross-section;

[0171] A covering material is attached to the columnar portion of the frame, such that the distal end of the columnar portion of the frame defines the blood inlet opening, and the impeller is configured to remain within 15 mm of the blood inlet opening throughout the entire operation of the impeller.

[0172] Part of the frame is shaped to reduce turbulence as blood flows from the blood inlet opening to the impeller.

[0173] For some applications, a portion of the framework includes a widened section of the framework.

[0174] For some applications, a portion of the frame is shaped to converge toward the impeller.

[0175] The invention will be more fully understood from the following detailed description of embodiments thereof, taken in conjunction with the accompanying drawings, in which: Brief description of the attached diagram

[0176] Figure 1A , Figure 1B and Figure 1C This is a schematic diagram of a ventricular assist device according to some applications of the present invention, wherein the distal end of the ventricular assist device is configured to be placed in the left ventricle of a subject;

[0177] Figure 2A , Figure 2B , Figure 2C , Figure 2D , Figure 2E and Figure 2F This is a schematic diagram of a frame housing an impeller for a ventricular assist device according to some applications of the present invention;

[0178] Figure 3A , Figure 3B , Figure 3C , Figure 3D , Figure 3E , Figure 3F , Figure 3G , Figure 3H , Figure 3I , Figure 3J and Figure 3K This is a schematic diagram of the impeller or a part thereof of a ventricular assist device according to some applications of the present invention;

[0179] Figure 4 This is a schematic diagram of an impeller disposed within a frame of a ventricular assist device according to some applications of the present invention;

[0180] Figure 5A and Figure 5B This is a schematic diagram of the impeller and frame of a ventricular assist device in a non-radial constraint state and a radial constraint state, respectively, according to some applications of the present invention;

[0181] Figure 5C This is a schematic diagram of a typical support assembly used in a blood pump based on an axial flow impeller in the prior art;

[0182] Figure 6A and Figure 6BThis is a schematic diagram of a ventricular assist device, according to some applications of the present invention, showing the impeller of the ventricular assist device at various stages of its motion cycle relative to the frame of the ventricular assist device.

[0183] Figure 6C This is a schematic diagram of a distal tip element of a ventricular assist device according to some applications of the present invention, the distal tip element including an axial shaft receiving tube and a distal tip portion;

[0184] Figure 6D This is a schematic diagram of an axial shaft of a ventricular assist device according to some applications of the present invention, wherein the axial shaft is at least partially covered or coated to reduce the gap between the axial shaft and a bushing of the impeller that slides on the axial shaft;

[0185] Figure 6E This is a schematic diagram of a bushing that slides on the axial shaft of a ventricular assist device according to some applications of the present invention, wherein the bushing of the axial shaft and the impeller is configured to prevent rotational movement of the bushing of the impeller relative to the axial shaft.

[0186] Figure 6F and Figure 6G This is a schematic diagram of an impeller housing according to some applications of the present invention, the impeller housing being configured to provide a gap between the impeller and the housing, the gap varying during the cardiac cycle of a subject;

[0187] Figure 7 This is a schematic diagram of the motor unit of a ventricular assist device according to some applications of the present invention;

[0188] Figure 8A and Figure 8B This is a schematic diagram of the motor unit of a ventricular assist device according to some applications of the present invention;

[0189] Figure 9 It is a graph showing how the length of the drive cable of the ventricular assist device changes with the pressure gradient resisted by the impeller of the blood pump as measured in experiments conducted by the inventors of this application.

[0190] Figure 10A , Figure 10B and Figure 10C This is a schematic diagram of the drive cable of a ventricular assist device according to some applications of the present invention;

[0191] Figure 10D , Figure 10E and Figure 10F This is a schematic diagram of the drive cable and axial shaft of a ventricular assist device according to some applications of the present invention;

[0192] Figure 11A and Figure 11BThis is a schematic diagram of an impeller according to some applications of the present invention, wherein the impeller is connected to an axial shaft at the distal end of the impeller and is not connected to an axial shaft at the proximal end of the impeller;

[0193] Figure 11C It is used to promote Figure 11A and Figure 11B A schematic diagram of the impeller press-fit connection part;

[0194] Figure 12A This illustrates when the impeller is configured as follows: Figure 11A The graph shown illustrates the relationship between the pressure gradient resisted by the impeller pump and the impeller pitch.

[0195] Figure 12B It is a graph showing the pressure-flow rate curves of impellers with corresponding pitches for some applications according to the present invention;

[0196] Figure 13A , Figure 13B and Figure 13C This is a schematic diagram of a process for cleaning drive cables and / or radial supports of a ventricular assist device according to some applications of the present invention;

[0197] Figure 13D This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including an expandable portion (e.g., a balloon) disposed around its distal tip portion, the expandable portion being configured to expand by fluid for cleaning the drive cables of the device;

[0198] Figure 13E This is a schematic diagram of a technique for reducing friction between a drive cable and an outer tube in which the drive cable rotates, and / or for reducing friction at a radial support of a ventricular assist device, according to some applications of the present invention.

[0199] Figure 14A , Figure 14B and Figure 14C This is a schematic diagram of a stator according to some applications of the present invention, the stator being configured to be disposed within a tube of a ventricular assist device, with a frame of the ventricular assist device impeller disposed nearby therein;

[0200] Figure 15A , Figure 15B , Figure 15C , Figure 15D and Figure 15E This is a schematic diagram of a stator embedded in a tube of a ventricular assist device according to some applications of the present invention;

[0201] Figure 16A and Figure 16BThis is a schematic diagram of a ventricular assist device including one or more ventricular blood pressure measuring tubes according to some applications of the present invention;

[0202] Figure 16C and Figure 16D This is a schematic diagram of a ventricular assist device having an aortic blood pressure measurement channel within a delivery catheter, according to some applications of the present invention;

[0203] Figure 16E This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including one or more sensors disposed on the outer surface of the tube of the device;

[0204] Figure 17A , Figure 17B , Figure 17C and Figure 17D This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including a pitot tube configured to measure blood flow through a tube of the device;

[0205] Figure 18 This is a schematic diagram of a ventricular assist device including coronary artery tubing and / or wires, according to some applications of the present invention;

[0206] Figure 19A , Figure 19B , Figure 19C , Figure 19D , Figure 19E , Figure 19F , Figure 19G and Figure 19H This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including an inner liner located on the inside of a frame housing an impeller;

[0207] Figure 20A , Figure 20B and Figure 20C This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including an inflatable portion (e.g., a balloon) disposed around its distal tip portion;

[0208] Figure 21 This is a schematic diagram of a ventricular assist device placed in the left ventricle of a subject according to some applications of the present invention, wherein a cross-sectional view of the left ventricle is shown;

[0209] Figure 22A , Figure 22B , Figure 22C and Figure 22D This is a schematic diagram of a distal tip element of a ventricular assist device according to some applications of the present invention, which is at least partially bent to define a question mark shape or a tennis racket shape;

[0210] Figure 23A and Figure 23B This is according to some applications of the present invention. Figure 22D A schematic diagram of a ventricular assist device, which is placed in the left ventricle of a subject;

[0211] Figure 24A , Figure 24B and Figure 24C This is a schematic diagram of a distal tip element according to some applications of the invention, the distal tip element being configured to center itself relative to the aortic valve of the subject;

[0212] Figure 25A , Figure 25B , Figure 25C , Figure 25D and Figure 25E This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including a tube configured to bend when blood is pumped through the tube;

[0213] Figure 25F This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device including a bending element made of shape memory material and configured to provide a predetermined curvature to a portion of the ventricular assist device;

[0214] Figure 26A , Figure 26B , Figure 26C , Figure 26D , Figure 26E and Figure 26F This is a schematic diagram of a ventricular assist device with at least a partially bent distal tip element according to some applications of the present invention;

[0215] Figure 27A , Figure 27B and Figure 27C This is a schematic diagram of a trauma-resistant protrusion according to some applications of the present invention, the trauma-resistant protrusion comprising a closed ellipse or closed circle and configured to extend distally from the distal tip element of a ventricular assist device;

[0216] Figure 28A This is a schematic diagram of a duckbill valve and a guide wire guide disposed at the distal end of an anti-wound tip according to some applications of the present invention.

[0217] Figure 28B and Figure 28C This is according to some applications of the present invention. Figure 28A A schematic diagram of the corresponding view of the duckbill valve;

[0218] Figure 28D and Figure 28EThis is according to some applications of the present invention. Figure 28A A schematic diagram of the corresponding view of the guide wire guide;

[0219] Figure 29 This is a schematic diagram of a delivery catheter according to some applications of the present invention, the delivery catheter including a sheath configured to facilitate reinsertion of the guide wire via percutaneous puncture;

[0220] Figure 30 This is a schematic diagram of a ventricular assist device including two impellers, according to some applications of the present invention;

[0221] Figure 31 This is a schematic diagram of a ventricular assist device including two impellers, according to some applications of the present invention;

[0222] Figure 32A , Figure 32B , Figure 32C , Figure 32D and Figure 32E This is a schematic diagram of a ventricular assist device according to some applications of the present invention, the ventricular assist device being configured to assist the function of the right ventricle in a subject; and

[0223] Figure 33 This is a schematic diagram of a vein assist device according to some applications of the present invention. Detailed Implementation

[0224] Now refer to Figure 1A , Figure 1B and Figure 1C These figures are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, wherein the distal end of the ventricular assist device is configured to be disposed in the left ventricle 22 of the subject. Figure 1A An overview of the ventricular assist device system, including console 21 and motor unit 23, is shown. Figure 1B A ventricular assist device inserted into the left ventricle of a subject is shown, and Figure 1C The pump portion 27 of the ventricular assist device is shown in more detail. The ventricular assist device includes a tube 24 that passes through the aortic valve 26 of the subject, such that the proximal end 28 of the tube is positioned within the subject's aorta 30, while the distal end 32 is positioned within the left ventricle 22. Typically, the tube 24 (sometimes referred to herein as the "blood pump tube") is an elongated tube, with its axial length typically much larger than its diameter. The scope of the invention includes the use of the instruments and methods described herein in anatomical locations other than the left ventricle and aorta. Therefore, the ventricular assist device and / or portions thereof are sometimes referred to herein (in the specification and claims) as a blood pump.

[0225] In some applications, ventricular assist devices (VADs) are used to assist left ventricular function in a subject during percutaneous coronary intervention (PCI). In this case, VADs are typically used for a duration of up to 10 hours (e.g., up to 6 hours), during which there is a risk of developing hemodynamic instability (e.g., during or immediately after PCI). Alternatively or additionally, VADs are used to assist left ventricular function in patients with cardiogenic shock for a longer period (e.g., 2-20 days, or 4-14 days), which can include any low cardiac output state (e.g., acute myocardial infarction, myocarditis, cardiomyopathy, postpartum, etc.). In some applications, VADs are used to assist left ventricular function in a subject for an even longer period (e.g., several weeks or months), for example, in bridge-to-recovery therapy. In some of these applications, the ventricular assist device is permanently or semi-permanently implanted, and the impeller of the ventricular assist device is percutaneously powered, for example, by using an external antenna magnetically coupled to the impeller.

[0226] like Figure 1B As shown, this figure illustrates the steps of deploying a ventricular assist device in the left ventricle. Typically, the distal end of the ventricular assist device is guided into the left ventricle via a guide wire 10. During insertion of the distal end of the device into the left ventricle, a delivery catheter 143 is positioned on the distal end of the device. Once the distal end of the device is positioned in the left ventricle, the delivery catheter is typically retracted into the aorta, and the guide wire is withdrawn from the subject's body. Typically, the retraction of the delivery catheter causes the self-expanding portion of the distal end of the device to exhibit a non-radial constraint configuration, as described in further detail below. Typically, the ventricular assist device is inserted into the subject to provide acute treatment. For some applications, in order to withdraw the left ventricular device from the subject at the end of treatment, the delivery catheter is advanced on the distal end of the device, causing the self-expanding portion of the distal end of the device to exhibit a radial constraint configuration. Alternatively or additionally, the distal end of the device is retracted into the delivery catheter, causing the self-expanding portion of the distal end of the device to exhibit a radial constraint configuration.

[0227] For some applications (not shown), the ventricular assist device and / or delivery catheter 143 includes an ultrasound transducer at its distal end, and the ventricular assist device is advanced toward the ventricle of the subject under ultrasound guidance.

[0228] Now refer to Figure 1CThe figure shows the pump portion 27 of the ventricular assist device 20 in more detail. Typically, an impeller 50 is disposed within the distal portion 102 of a tube 24 and configured to pump blood from the left ventricle into the aorta by rotation. The tube typically defines one or more blood inlet openings 108 at its distal end, through which blood flows from the left ventricle into the tube during impeller operation. For some applications, the proximal portion 106 of the tube defines one or more blood outlet openings 109, through which blood flows from the tube into the ascending aorta during impeller operation.

[0229] For some applications, this typically includes the console 21 of the computer processor 25 (such as...). Figure 1A (As shown) drives the impeller to rotate. For example, a computer processor can control motor 74 (such as...) Figure 7 As shown), motor 74 is installed in motor unit 23 (e.g. Figure 1A (as shown) inside, and via drive cable 130 (as shown) Figure 7 (As shown) drives the impeller to rotate. For some applications, the computer processor is configured to detect physiological parameters of the subject (e.g., left ventricular pressure, cardiac afterload, rate of change of left ventricular pressure, etc.) and control the rotation of the impeller in response, as described in further detail below. Typically, the operations performed by the computer processor described herein, depending on the memory technology used, convert the physical state of the memory into different magnetic polarities, charges, etc., the memory being a real physical artifact communicating with the computer processor. The computer processor 25 is typically a hardware device programmed with computer program instructions to produce a dedicated computer. For example, when programmed to perform the techniques described herein, the computer processor 25 typically acts as a dedicated ventricular assist computer processor and / or a dedicated blood pump computer processor.

[0230] For some applications, cleaning system 29 (in) Figure 1A As shown in the diagram, a driving fluid (e.g., a glucose solution) passes through multiple parts of the ventricular assist device 20, for example, to cool multiple parts of the device and / or to flush debris from multiple parts of the device. The cleaning system 29 will be described in further detail below.

[0231] Typically, a frame 34 is disposed within the tube 24, surrounding the impeller 50, along the distal portion 102 of the tube 24. The frame is typically made of a shape memory alloy, such as nitinol. For some applications, the shape memory alloy of the frame is shaped such that at least a portion of the frame (and therefore the distal portion 102 of the tube 24) presents a generally circular, elliptical, or polygonal cross-sectional shape when no force is applied to the distal portion 102 of the tube 24. By presenting the generally circular, elliptical, or polygonal cross-sectional shape of the frame, the frame is configured to hold the distal portion of the tube in an open state. Typically, during operation of the ventricular assist device, the distal portion of the tube is configured to be placed within the subject's body such that the distal portion of the tube is at least partially disposed within the left ventricle.

[0232] For some applications, along the proximal portion 106 of tube 24, the frame is not disposed within the tube, so the tube is not supported by frame 34 in the open state. Tube 24 is typically made of a blood-impermeable, collapsible material. For example, tube 24 may comprise polyurethane, polyester, and / or silicone. Alternatively or additionally, the tube may be made of polyethylene terephthalate (PET) and / or polyether block amide (e.g., It is made of [material name missing]. For some applications (not shown), the tube is reinforced with a braided reinforcement structure, such as a braided nitinol tube. Typically, the proximal portion of the tube is configured to be positioned such that it is at least partially located within the subject's ascending aorta. For some applications, the proximal portion of the tube passes through the subject's aortic valve, entering the subject's ascending aorta from the subject's left ventricle, such as [example missing]. Figure 1B As shown. As described above, the tube typically defines one or more blood inlet openings 108 at its distal end, through which blood flows from the left ventricle into the tube during impeller operation. For some applications, the proximal portion of the tube defines one or more blood outlet openings 109, through which blood flows from the tube into the ascending aorta during impeller operation. Typically, the tube defines multiple blood outlet openings 109, for example, between two and eight blood outlet openings (e.g., between two and four blood outlet openings). During impeller operation, the blood flow pressure through the tube typically keeps the proximal portion of the tube open. For some applications, such as in the event of impeller failure, the proximal portion of the tube is configured to collapse inward in response to pressure outside the proximal portion of the tube exceeding the pressure inside the proximal portion. In this way, the proximal portion of the tube acts as a safety valve, thereby preventing retrograde blood flow from the aorta into the left ventricle.

[0233] Refer again Figure 1CFor some applications, frame 34 is shaped such that it defines a proximal conical portion 36, a central cylindrical portion 38, and a distal conical portion 40. Typically, the proximal conical portion is such that the narrow end of the cone is proximal to the wide end of the cone. More typically, the distal conical portion is such that the narrow end of the cone is distal to the wide end of the cone. For some applications, tube 24 extends to the end of cylindrical portion 38 (or slightly proximal or distal thereto) such that the distal end of the tube defines a single axially oriented blood inlet opening 108, as... Figure 1C As shown. For some applications, within at least a portion of frame 34, lining 39 rests on the frame, as described below. Figures 19A-19H As described above. Depending on the application, the liner partially or completely overlaps with the tube 24 on the liner-lined portion of the frame. For such applications, the distal end of the liner defines a single axially oriented blood inlet opening 108. For some applications (not shown), the tube 24 extends to the end of the distal tapered portion 40, and the tube defines one or more lateral blood inlet openings (not shown), for example, as described in US2019 / 0209758 of Tuval, which is incorporated herein by reference. For such applications, the tube typically defines two to four lateral blood inlet openings.

[0234] Typically, tube 24 includes a conical proximal portion 42 and a cylindrical central portion 44. The proximal conical portion is typically positioned such that the narrow end of the cone is proximal to the wide end. Typically, the blood outlet opening 109 is defined by tube 24 such that the opening extends at least partially along the proximal conical segment of tube 24. For some such applications, the blood outlet opening is teardrop-shaped, such as... Figure 1C As shown. Typically, the teardrop-shaped property of the blood outlet opening is combined with an opening that extends at least partially along the proximal conical segment of tube 24, such that blood flows out of the blood outlet opening at its location along a flow line substantially parallel to the longitudinal axis of tube 24.

[0235] As described above, for some applications (not shown), the tube extends to the end of the distal tapered portion 40 of the frame 34. In such applications, the tube typically defines the distal tapered portion, where the narrow end of the cone is distal relative to the wide end. For some applications (not shown), the diameter of the tube 24 varies along the length of the central portion of the tube, such that the central portion of the tube has a truncated cone shape. For example, the central portion of the tube may widen from its proximal end to its distal end, or it may narrow from its proximal end to its distal end. For some applications, at its proximal end, the central portion of the tube has a diameter between 5 mm and 7 mm, while at its distal end, the central portion of the tube has a diameter between 8 mm and 12 mm.

[0236] Refer again Figure 1CA typical ventricular assist device includes a distal tip element 107 disposed distally relative to the frame 34 and including an axial shaft receiving tube 126 and a distal tip portion 120, both of which will be described in further detail below.

[0237] Now refer to Figure 2A , Figure 2B , Figure 2C , Figure 2D , Figure 2E and Figure 2F These figures are schematic diagrams of a frame 34 housing the impeller of a ventricular assist device 20 according to some applications of the present invention. As described above, the frame 34 is typically made of a shape memory alloy such as nitinol, and the shape memory alloy of the frame is shaped such that the frame (and therefore the tube 24) has a generally circular, elliptical, or polygonal cross-sectional shape when no force is applied to the tube 24. By presenting its generally circular, elliptical, or polygonal cross-sectional shape, the frame is configured to hold the distal portion of the tube in an open state.

[0238] Typically, the frame is a scaffold-like frame because it comprises pillars that sequentially define the cells. More typically, the frame is covered by tube 24 and / or by lining 39, as described below. Figures 19A-19H As described below, for some applications, the impeller 50 reciprocates axially relative to the frame 34. Typically, during the movement of the impeller relative to the frame, the portion of the impeller defining its maximum span is positioned within the cylindrical portion 38 of the frame 34. In some cases, if the cell of the cylindrical portion 38 of the frame 34 is too large, the tube 24 and / or liner 39 is stretched between the edges of the cell, causing the tube 24 and / or liner 39 to not define a circular cross-section. For some applications, if this occurs in the area where the portion defining the impeller's maximum span is positioned, this results in a non-constant gap between the edge of the impeller blades and the tube 24 (and / or liner) at that location during the impeller's rotation cycle. For some applications, this may lead to increased hemolysis compared to a situation where there is a constant gap between the edge of the impeller blades and the tube 24 (and / or liner) at that location during the impeller's rotation cycle.

[0239] Reference Figure 2AAt least in part, taking into account the problems described in the previous paragraph, within the columnar portion 38 of frame 34, the frame defines a large number of relatively small cells. Typically, when the frame is configured with its non-radial constraint, the maximum cell width CW (i.e., the distance from the inner edge of the support at the center joint on one side of the cell to the inner edge of the support at the center joint on the other side of the cell, as measured around the circumference of columnar portion 38) of each cell within the columnar portion of the frame is less than 2 mm, for example, between 1.4 mm and 1.6 mm, or between 1.6 mm and 1.8 mm. Due to the relatively small size of the cells, tube 24 (and / or liner) defines a substantially circular cross-section within the columnar portion of the frame.

[0240] Still refer to Figure 2A And starting from the proximal end of the frame (on the left side of the figure), the frame typically defines the following portion: (a) a connecting portion 31, through which the frame is connected to the proximal support 116 of the ventricular assist device (in Figure 4 (a) shown in the diagram, (b) the proximal conical portion 36, (c) the cylindrical portion 38, (d) the distal conical portion 40, and (e) the distal strut joint 33. As shown, as the frame transitions from the proximal end of the frame to the center of the frame (e.g., as the frame passes through the connecting portion 31, through the proximal conical portion 36, and transitions to the cylindrical portion 38), the struts 37 of the frame pass through joints 35, where two struts branch off from a single strut in a Y-shape. As described in further detail below, typically, the frame 34 is placed in the delivery conduit 143 in a radially constrained (i.e., crimped) configuration by being axially elongated within the frame. Furthermore, typically, the frame transmits its radial narrowing to the impeller, and the impeller becomes radially constrained by being axially elongated within the frame. For some applications, the struts of the frame configured as described above facilitate the transmission of axial elongation from the delivery conduit (or other means configured to crimp the frame) to the frame, which in turn facilitates the transmission of axial elongation to the impeller. This is because the pairs of struts branching out from each joint 35 are configured to pivot around the joint and move closer to each other, thus closing.

[0241] Still refer to Figure 2A For some applications, when the frame is connected to the axial shaft 92 (in... Figure 2D When (as shown in the diagram), the distal support joint 33 remains open so that the impeller is placed within the frame via the distal end of the frame. Subsequently, the distal support portion closes around the outside of the distal support 118, as shown below. Figures 5A-5B Further detailed description. For some applications, the proximal end of the distal tip element 107 ( Figure 1C (As shown) the distal support sections are kept in a closed configuration around the outside of the distal support 118.

[0242] Typically, when frame 34 is configured in its non-radial constraint configuration, the total length of frame 34 is greater than 25 mm (e.g., greater than 30 mm) and / or less than 50 mm (e.g., less than 45 mm), for example, 25 mm–50 mm or 30 mm–45 mm. Typically, when frame 34 is configured in its radial constraint configuration (within delivery conduit 143), the length of frame is increased by 2 mm to 5 mm. Typically, when frame 34 is configured in its non-radial constraint configuration, the length of the cylindrical portion of frame 34 is greater than 10 mm (e.g., greater than 12 mm) and / or less than 25 mm (e.g., less than 20 mm), for example, 10 mm–25 mm or 12 mm–20 mm. For some applications, the ratio of the length of the cylindrical portion of the frame to the total length of the frame is greater than 1:4 and / or less than 1:2, for example, between 1:4 and 1:2.

[0243] Now refer to Figure 2B The figure is a schematic diagram of the pump portion of a ventricular assist device 20 according to some applications of the present invention, wherein at least a portion of the cylindrical portion 38 of the frame 34 of the ventricular assist device has a helical structure 55. For some applications, at least a portion of the cylindrical portion 38 of the frame 34 of the ventricular assist device has a helical structure 55 so that the tube 24 (and / or liner) defines a substantially circular cross-section within the cylindrical portion of the frame, for example, for the reasons provided above.

[0244] Now refer to Figure 2C The figure is a schematic diagram of frame 34, which transitions from its end to its maximum diameter (i.e., the cylindrical portion of the frame) over a relatively short distance D. Typically, this results in a ratio of the cylindrical portion of the frame to the total length of the frame that is greater than the ratio described above. For example, the ratio of the cylindrical portion of the frame to the total length of the frame can be greater than 1:2 or greater than 2:3. More typically, this results in a larger angle at which the frame widens within the tapered portion compared to the case where the cylindrical portion has a shorter relative length (assuming all other cases are the same). In turn, for some applications, this reduces vibration of the frame during impeller rotation. As mentioned above, to reduce hemolysis, it is typically desirable to maintain a constant clearance between the edges of the impeller blades and the tube 24 (and / or liner 39). Therefore, it is typically desirable to reduce vibration of the frame relative to the impeller.

[0245] Now refer to Figure 2DThe figure is a schematic diagram of the pump portion of a ventricular assist device according to some applications of the present invention, the ventricular assist device including an expandable impeller housing 60. For some applications, instead of having a frame 34 surround the impeller, the expandable housing surrounds the impeller. For some applications, at least in the region of the housing surrounding the impeller, the frame is configured to define an internal circular cross-section such that a constant gap exists between the edge of the impeller blades and the inner wall of the housing during the impeller's rotation cycle.

[0246] Typically, for example Figure 2D In the illustrated application, proximal and distal support frames 61 are disposed within an expandable impeller housing. The support frames are configured to act as radial supports relative to the axial shaft 92 (described below) coupled to the impeller 50. For some applications, the impeller housing is made of a flexible and expandable material. Typically, the impeller housing is inserted into the left ventricle in a reduced state and expands once disposed within the left ventricle, for example, to take on its deployment shape. Typically, tube 24 extends proximally from the expandable impeller housing. For some applications, tube 63 runs along tube 24 (e.g., the inner or outer surface of the tube), and the expandable housing is expanded via the tube. For some applications, the impeller housing is expanded with saline and / or a different solution (e.g., a glucose solution). For some applications, the expandable impeller housing defines one or more blood inlet openings 108.

[0247] Now refer to Figure 2E and Figure 2F These figures are schematic diagrams of the flat outline of a frame 34 according to some applications of the invention, the frame being generally configured as follows Figure 2A As shown. Typically, frame 34 is laser-cut from a tube of shape memory alloy (e.g., nitinol). Figure 2E and Figure 2F The outline shown depicts (for illustrative purposes) how the frame of the device would appear if, before shaping the frame, a longitudinal cut was made at a given circumferential position along the length of the frame, and then the frame was laid flat on a surface. For some applications, within the columnar portion 38 of the frame, cells are cut by causing a laser to cut along the peripheral outline of the cell, such as... Figure 2E The enlarged portion is shown. As mentioned above, typically within the cylindrical section, the cells are relatively small, which means cutting a relatively large number of cells within the circumference of the frame. Due to the size of the laser used to cut the cells, it can be challenging to make the laser travel around the entire perimeter of the cell. However, near the joints, it is desirable for the cells to be rounded to reduce strain at the joints. Therefore, for some applications, roughly as... Figure 2FThe columnar portion of the frame is cut as shown. That is, at the joint 35, a rounded edge 41 is laser-cut. However, between the joints, a single slit 43 is laser-cut, rather than cutting around the perimeter of the cell.

[0248] Now refer to Figures 3A-3C These figures are schematic diagrams of an impeller 50 or portions thereof according to some applications of the invention. Typically, the impeller includes at least one outer helical elongated element 52 wound around a central axial spring 54, such that the helical structure defined by the helical elongated element is coaxial with the central axial spring. Typically, the impeller includes two or more helical elongated elements (e.g., three helical elongated elements, such as…). Figures 3A-3C (As shown). For some applications, the helical elongated element and the central axial spring are made of shape memory materials, such as shape memory alloys like nitinol. Typically, each helical elongated element and the central axial spring is supported by a membrane 56 of material (e.g., an elastomer, such as polyurethane, and / or silicone) between them. For some applications, the membrane of the material includes nitinol sheets embedded therein, for example, to reinforce the membrane of the material. For illustrative purposes, the impeller in Figure 3A The text indicates that the material is not available. Figure 3B and Figure 3C Views of the impeller are shown, in which the material is supported between a helical elongated element and a spring.

[0249] Each helical elongated element, together with a membrane extending from the helical elongated element to the spring, defines the blades of the corresponding impeller, wherein the helical elongated element defines the outer edge of the blade, and the axial spring defines the axis of the impeller. Typically, the membrane of material extends along the spring and covers the spring. For some applications, the suture 53 (e.g., polyester suture, such as...) Figure 3B and Figure 3C The suture (as shown) is wound around a helical elongated element, for example, as described in Schwammenthal's US 2016 / 0022890, which is incorporated herein by reference. Typically, the suture is configured to facilitate bonding between a film of material (typically an elastomer, such as polyurethane, or silicone) and a helical elongated element (typically a shape memory alloy, such as nitinol). For some applications, the suture (e.g., polyester suture, not shown) is wound around a spring 54. Typically, the suture is configured to facilitate bonding between a film of material (typically an elastomer, such as polyurethane, or silicone) and a spring (typically a shape memory alloy, such as nitinol).

[0250] Figure 3CEnlarged views A and B illustrate two alternative arrangements in which the suture is secured around the helical elongated element 52. For some applications, the suture is secured around the outer surface of the helical elongated element, as shown in enlarged view A. Alternatively, the helical elongated elements define a groove 45 on their outer surface, and the suture is embedded within the groove, as shown in enlarged view B. Typically, by embedding the suture within the groove, the suture does not increase the outer profile of the impeller, and the outer profile of the impeller is defined by the outer surface of the helical elongated element.

[0251] Typically, the proximal ends of spring 54 and helical elongated element 52 extend from the proximal bushing (i.e., sleeve support) 64 of the impeller, such that the proximal ends of spring 54 and helical elongated element 52 are positioned at similar radial distances from the longitudinal axis of the impeller. Similarly, typically, the distal ends of spring 54 and helical elongated element 52 extend from the distal bushing 58 of the impeller, such that the distal ends of spring 54 and helical elongated element 52 are positioned at similar radial distances from the longitudinal axis of the impeller. Typically, spring 54, as well as the proximal bushing 64 and distal bushing 58 of the impeller, define an inner cavity 62 (e.g., ...) passing through it. Figure 3C (As shown).

[0252] Now refer to Figure 4 This figure is a schematic diagram of an impeller 50 disposed within a frame 34 of a ventricular assist device 20 according to some applications of the present invention. For some applications, a liner 39 is fitted onto the frame within at least a portion of the frame 34, as described below. Figures 19A-19H As described. Depending on the application, the liner partially or completely overlaps with the tube 24 on the liner-lined portion of the frame. Figure 4 In the illustrated application, the liner is nested within the columnar portion of the frame, and tube 24 does not cover the columnar portion of the frame. However, the scope of this application includes references to... Figure 4 The instruments and methods described herein apply to the following references Figures 19A-19H Any of the applications described.

[0253] like Figure 4 As shown, typically, a gap G exists between the outer edge of the impeller 50 and the liner 39, even at the location of the largest impeller span. For some applications, it is desirable that the gap between the outer edge of the impeller blades and the liner 39 be relatively small so that the impeller can effectively pump blood from the subject's left ventricle into the subject's aorta. However, it is also desirable that the gap between the outer edge of the impeller blades and the inner surface of the frame 34 remain substantially constant throughout the rotation of the impeller within the frame 34, for example, to reduce the risk of hemolysis.

[0254] For some applications, when both the impeller and frame 34 are configured in a non-radial constraint configuration, at the location of the largest impeller span, the gap G between the outer edge of the impeller and the liner 39 is greater than 0.05 mm (e.g., greater than 0.1 mm) and / or less than 1 mm (e.g., less than 0.4 mm), for example, 0.05 mm–1 mm or 0.1 mm–0.4 mm. For some applications, when the impeller is configured in its non-radial constraint configuration, at the location of the largest impeller outer diameter, the outer diameter of the impeller is greater than 7 mm (e.g., greater than 8 mm) and / or less than 10 mm (e.g., less than 9 mm), for example, 7 mm–10 mm or 8 mm–9 mm. For some applications, when frame 34 is configured in its non-radial constraint configuration, the inner diameter of frame 34 (measured from the inside of liner 39 on one side of the frame to the inside of liner on the opposite side of the frame) is greater than 7.5 mm (e.g., greater than 8.5 mm), and / or less than 10.5 mm (e.g., less than 9.5 mm), for example, 7.5 mm–10.5 mm, or 8.5 mm–9.5 mm. For some applications, when frame 34 is configured in its non-radial constraint configuration, the outer diameter of frame 34 is greater than 8 mm (e.g., greater than 9 mm), and / or less than 13 mm (e.g., less than 12 mm), for example, 8 mm–13 mm, or 9 mm–12 mm.

[0255] Typically, the axial shaft 92 passes through the impeller's inner cavity 62 along the axis of the impeller 50. More typically, the axial shaft is rigid, such as a rigid tube. For some applications, the proximal bushing 64 of the impeller is coupled to the shaft such that the axial position of the proximal bushing relative to the shaft is fixed, and the distal bushing 58 of the impeller is slidable relative to the shaft. The axial shaft itself is radially stable via the proximal radial support 116 and the distal radial support 118. In turn, the axial shaft radially stabilizes the impeller relative to the inner surface of the frame 34 by passing through the inner cavity 62 defined by the impeller, such that a relatively small clearance (e.g., the clearance described above) is maintained between the outer edge of the impeller blades and the inner surface of the frame 34, even during impeller rotation.

[0256] Refer again Figures 3A-3CFor some applications, the impeller includes a plurality of elongated elements 67 extending radially from a central axial spring 54 to an outer helical elongated element 52. These elongated elements are typically flexible, but substantially non-stretchable along the axis defined by the elongated elements. More typically, each elongated element is configured not to exert a force on the helical elongated element unless a force is applied to the impeller causing the helical elongated element to move radially outward, thus (in the absence of elongated elements) the spacing between the helical elongated element and the central axial spring will be greater than the length of the elongated element. For example, the elongated elements may comprise ropes (e.g., polyester, and / or another polymer or a natural material containing fibers) and / or threads (e.g., nitinol thread, and / or threads made of different alloys or metals).

[0257] For some applications, the elongated element 67 holds the helical elongated element (which defines the outer edge of the impeller blades) within a given distance relative to the central axial spring. In this way, the elongated element is configured to prevent the outer edge of the impeller from being pushed radially outward due to the forces applied to the impeller during impeller rotation. The elongated element is thus configured to maintain the gap between the outer edge of the impeller blades and the inner surface of the frame 34 during impeller rotation. Typically, more than one (e.g., more than two) and / or fewer than eight (e.g., fewer than four) elongated elements 67 are used in the impeller, wherein each elongated element is typically folded in half (i.e., extending radially from the central axial spring 54 to the outer helical elongated element 52 and then returning from the helical elongated element to the central axial spring). For some applications, multiple elongated elements are formed from a single piece of rope or a single line, wherein each elongated element extends from the spring to the corresponding helical elongated element and returns to the spring, as described in further detail below.

[0258] For some applications, the impeller is manufactured as follows. The proximal bushing 64, the distal bushing 58, and the helical elongated element 52 are cut from a tube of shape memory material (e.g., nitinol). The cutting of the tube and the shaping of the shape memory material are typically performed such that the helical elongated element is defined by the shape memory material, for example, using a technique substantially similar to that described in Schwammenthal's US2016 / 0022890. Typically, a spring 54 is inserted into the cut and shaped tube such that the spring extends at least along the length of the tube from the proximal bushing to the distal bushing. For some applications, the spring is inserted into the cut and shaped tube when it is in an axially compressed state, and the spring is configured to remain in place relative to the tube by applying radial forces on the proximal and distal bushings. Alternatively or additionally, multiple portions of the spring are welded to the proximal and distal bushings. For some applications, the spring is cut from a tube of shape memory material (e.g., nitinol). For some such applications, the spring is configured such that when the spring is set in a non-radial constraint configuration (where the spring is typically set in a non-radial constraint configuration during impeller operation), there is essentially no gap between the spring coil and its adjacent coil.

[0259] For some applications, after the spring 54 is inserted into the cutting and shaping tube, the elongated element 67, as described above, is positioned to extend between the spring and one or more helical elongated elements, for example, in the following manner. A mandrel (e.g., a polyetheretherketone (PEEK) and / or polytetrafluoroethylene (PTFE) mandrel) is inserted through the cavity defined by the spring and bushing. A rope or thread is then threaded through such that it (a) from the mandrel to the first helical elongated element, (b) from the first helical elongated element back to the mandrel, (c) around the mandrel and to the second helical elongated element, (d) from the second helical elongated element back to the mandrel, and so on. Once the rope or thread has been threaded from the mandrel to each helical elongated element and back again, the ends of the rope or thread are joined together, for example, by tying them together. For some applications, suture 53 (e.g., polyester suture) is wound around a helical elongated element to facilitate bonding between a film of material (typically an elastomer, such as polyurethane, or silicone) and the helical elongated element (typically a shape memory alloy, such as nitinol) in later stages of impeller manufacturing. For some applications, suture (e.g., polyester suture, not shown) is wound around a spring 54. Typically, the suture is configured to facilitate bonding between a film of material (typically an elastomer, such as polyurethane, or silicone) and the spring (typically a shape memory alloy, such as nitinol) in later stages of impeller manufacturing.

[0260] Typically, at this stage, components such as Figure 3A The structure 59 is shown. This structure includes a cut and shaped tube defining a proximal bushing and a distal sleeve, a helical elongated element and a spring (and optionally, an elongated element and a suture). The structure is immersed in the material defining the membrane 56. For some applications, the assembled structure is immersed in the material with its central axis positioned through the cavity defined by the spring and bushing, although it should be noted that the mandrel is not in the... Figure 3A As shown in the diagram. Typically, the material used to form the membrane is silicone and / or polyurethane (and / or similar elastomers), and the assembled structure is immersed in the material while it is in an uncured liquid state. Subsequently, the material is cured, causing it to solidify, for example, by drying it. Once the material has dried, the mandrel is typically removed from the cavity defined by the bushing and spring.

[0261] Typically, the result of the above process is that a continuous film of material extends between each helical elongated element and the spring, and this continuous film of material also extends along the length of the spring to define a tube in which the spring is embedded. The portion of the film extending from each helical elongated element to the spring defines the blades of the impeller. For applications where the impeller includes elongated elements 67, the elongated elements are typically embedded within these portions of the film.

[0262] Typically, impeller 50 is inserted into the left ventricle via a conduit, while impeller 50 is in a radially constrained configuration. In this configuration, both the helical elongated element 52 and the central axial spring 54 become axially elongated and radially constrained. Typically, the membrane 56 of a material (e.g., silicone and / or polyurethane) changes shape to correspond to the shape changes of the helical elongated element and the axially supporting spring (both of which support the membrane of the material). Typically, using a spring to support the inner edge of the membrane allows the membrane to change shape without breaking or collapsing because the spring provides a large surface area bound by the inner edge of the membrane. For some applications, using a spring to support the inner edge of the membrane reduces the diameter of the impeller that might be radially constrained compared to, for example, using a rigid shaft to support the inner edge of the membrane, because the diameter of the spring itself can be reduced by making the spring axially elongated.

[0263] As described above, for some applications, the proximal bushing 64 of the impeller 50 is coupled to the axial shaft 92 such that the axial position of the proximal bushing relative to the shaft is fixed, while the distal bushing 58 of the impeller is slidable relative to the shaft. For some applications, when the impeller is radially restrained for insertion into the ventricle or removal from the subject, the impeller axially elongates by sliding the distal bushing distally along the axial shaft. For example... Figures 3A-3C As shown, after being released into the subject's body, the impeller exhibits its non-radial constraint configuration (where the impeller is typically set to a non-radial constraint configuration during impeller operation).

[0264] Note that, for illustrative purposes, in some figures, the impeller 50 is shown as not including, as referenced. Figures 3A-3C All features of the impellers shown and described. For example, some figures illustrate impellers excluding the suture 53 and / or the elongated element 67. The scope of this application includes the use of any apparatus and method described herein with regard to Figures 3A-3C Impellers with any of the features shown and described.

[0265] Now refer to Figure 3D , Figure 3E and Figure 3F These figures are schematic diagrams of an impeller 50 or portions thereof for some applications according to the present invention. As described above, for some applications, the impeller 50 includes a suture 53. The suture 53 is wound around a helical elongated element 52 and is configured to facilitate bonding between a film of material (typically an elastomer, such as polyurethane, or silicone) and the helical elongated element (typically a shape memory alloy, such as nitinol).

[0266] As an alternative to or supplement to suture 53, for some applications, coil 68 is wound around (or placed on) a spiral elongated element, such as... Figure 3D As shown. For example, tightly wound coils (e.g., tightly wound nitinol coils) can be wound (or placed) around each helical elongated element. Typically, the coils facilitate bonding between the film of material and the helical elongated element by increasing the surface area of ​​the material bonded at the interface between the material and the helical elongated element. For some applications, structure 59 is modularly formed (e.g., see reference below). Figure 3F (as described above). For some such applications, the coil is positioned around each elongated element 52 before the elongated element is coupled to the proximal and distal bushings of the impeller (e.g., by sliding the entire coil over the elongated element with a single action).

[0267] As a further alternative or supplement to the suture 53, for some applications, the sleeve 69 is placed around the spiral elongated element, such as... Figure 3EAs shown. For example, such a sleeve can be made of a polymer, such as polyester. Typically, the sleeve promotes bonding between the film of the material and the helical elongated element by increasing the surface area of ​​the material bonded at the interface between the material and the helical elongated element. For some applications, the sleeve acts as an intermediary between the material that makes the elongated element and the material that makes the film 56, the material that makes the elongated element typically having relatively high stiffness (and is typically nitinol), and the material that makes the film 56 typically being an elastomer with relatively low stiffness. Thus, when the material dries, the sleeve enhances the bond strength between the material and the helical elongated element. For some applications, the sleeve 69 is applied to structure 59. For some such applications, a longitudinal slit is formed in the sleeve to allow the sleeve to be placed around the helical elongated element 52. After placement around the helical elongated element 52, the slit is closed (e.g., by stitching or adhesive). For some applications, structure 59 is formed modularly (e.g., as described below). Figure 3F (as described above). For some such applications, a sleeve is placed around the elongated element 52 before the elongated element is connected to the proximal and distal bushings of the impeller.

[0268] As another alternative or supplement to the suture 53, for some applications, the elongated element 52 is shaped to have a rounded (e.g., circular) cross-section, such as... Figure 3F The right side is shown (which shows a cross-sectional view of an elongated element with a rounded cross section). Figure 3F The left portion shows a cross-sectional view of the elongated element 52, where, for cases where the elongated element has a non-rounded cross-section (e.g., a square or rectangular cross-section), the material of the membrane 56 is bonded to the elongated element. As shown, this is sometimes the case where the material used to make the membrane (e.g., silicone and / or polyurethane) forms a thinner layer at the corners of the elongated element with a non-rounded cross-section. In contrast, as... Figure 3F As shown in the left portion, when an elongated element has a rounded cross-section, the material typically forms a layer of substantially uniform thickness at the interface with the elongated element. Therefore, for some applications, elongated elements have rounded cross-sections.

[0269] For some applications, the proximal bushing 64 and distal bushing 58, as well as the elongated element 52, are cut from an alloy tube, as described above. In such applications, the elongated element typically has non-rounded edges after the tube is cut. Therefore, for some applications, the edges of the elongated element are rounded after the tube is cut, for example, using grinding, sandblasting, tumbling, etching, plasma, surface charging, and / or by adding rounded edges to the elongated element. Alternatively, the proximal and distal bushings and the elongated element can be formed in a modular manner and can subsequently be joined to each other (e.g., via welding and / or forging). For some such applications, the elongated element joined to the proximal and distal bushings has a rounded cross-section. (Refer to above) Figure 3E According to the description, for some applications, the bushing 69 is placed on the elongated element before the elongated element is attached to the proximal bushing and / or before the elongated element is attached to the distal bushing.

[0270] For some applications, alternative or additional techniques are used to facilitate bonding between the film of the material and the helical elongated element. For example, surface treatments (e.g., grinding, sandblasting, tumbling, etching, plasma, surface charging, etc.) can be used to treat the helical elongated element to roughen its outer surface.

[0271] Based on the above Figures 3A-3FAs described above, for some applications of the invention, the impeller 50 is manufactured in such a way that it has a first bushing 64 and a second bushing 58 at its proximal and distal ends, the first and second bushings being connected to each other by at least one elongated element 52. The at least one elongated element is formed to be at least partially radially expanded by axial compression of the structure and to form at least one helical elongated element. An elastomeric material is coupled to the at least one helical elongated element such that the at least one helical elongated element with the coupled elastomeric material defines the blades of the impeller. Typically, the coupling is performed such that layers of material are disposed around the radially outer edge of the at least one helical elongated element, the layers of material forming the effective edge of the impeller blades (i.e., at which the blood pumping function of the impeller is substantially no longer effective). More typically, the method includes performing a step of reinforcing the bonding of the elastomeric material to the at least one helical elongated element in a manner that does not cause it to protrude from the effective edge of the impeller blades. For example, suture 53 can be placed within a groove defined by at least one helical elongated element, such that the suture does not protrude from the radial outer edge of the helical elongated element, the suture being configured to reinforce the bonding of the elastomeric material with the at least one helical elongated element. Alternatively or additionally, a tightly wound coil 68 can be placed around the at least one helical elongated element, such that the elastomeric material forms a substantially smooth layer along the radial outer edge of the coil, the coil being configured to reinforce the bonding of the elastomeric material with the at least one helical elongated element. Further alternatively or additionally, a sleeve 69 can be placed around the at least one helical elongated element, such that the elastomeric material forms a substantially smooth layer along the radial outer edge of the sleeve, the sleeve being configured to reinforce the bonding of the elastomeric material with the at least one helical elongated element. For some applications, a rounded cross-section is provided for the at least one helical elongated element, such that the elastomeric material forms a substantially uniform layer of thickness at the interface between the elastomeric material and the helical elongated element. As described above, it is typically desirable that the outer edge of the impeller blades and the liner 39 (e.g.) Figure 4 The gap G between the blades (as shown) is relatively small. Therefore, it is desirable that the effective edge of the impeller blades does not protrude, as this would occupy part of the gap between the outer edges of the impeller blades (thus requiring a larger gap) without increasing the effectiveness of the impeller's blood pumping function.

[0272] Now refer to Figure 3G and Figure 3HThese figures are schematic diagrams of an elongated element 67 extending between each helical elongated element 52 and spring 54, according to some applications of the invention. For some applications, a corresponding annular elongated element 67 extends between each helical elongated element and spring. Typically, the annular elongated element is a closed loop having a predetermined length and being (substantially) non-stretchable. The length of the annular elongated element is typically predetermined so as to hold the helical elongated element (which defines the outer edge of the impeller blades) within a given distance relative to the central axial spring during impeller rotation, and thereby maintain the clearance between the outer edge of the impeller blades and the inner surface of the frame 34, as described above. For some applications, such as... Figure 3G and Figure 3H As shown in the enlarged portion, the impeller is formed by wrapping the first end of an annular elongated element around each helical elongated element. Subsequently, a spring 54 is inserted, passing through the proximal bushing 64 and the distal bushing 58, and through the second end of the annular helical elongated element.

[0273] For some applications, at the longitudinal center position of spring 54, the spring is shaped as a defining tube 70 (i.e., without a coil), such as... Figure 3G and Figure 3H As shown. Typically, the second end of the annular elongated element surrounds the tube at the longitudinal center of the spring. Typically, this reduces the risk of tearing of the annular elongated element compared to a loop around the spring with the second end of the annular elongated element. For some applications (not shown), the tube defines a groove therein, and the second end of the annular elongated element is configured to be held within the groove.

[0274] In some applications, a ring-shaped elongated element surrounds the body of a spiral-shaped elongated element, such as... Figure 3G The magnified portion is shown below. Figure 3G Enlarged views A and B illustrate two alternative configurations in which the annular elongated element surrounds the body of the helical elongated element. For some applications, the annular elongated element surrounds the outer surface of the helical elongated element, as shown in enlarged view A. Alternatively, the helical elongated element is defined by a groove 45 on its outer surface, and the annular elongated element surrounds the groove 45 (e.g., is embedded within the groove), as shown in enlarged view B. By embedding the annular elongated element within the groove, the annular elongated element typically does not increase the outer profile of the impeller, and the outer profile of the impeller is defined by the outer surface of the helical elongated element.

[0275] For some applications, the spiral elongated element is shaped to define two holes 71, the two holes 71 being positioned very close to each other, and the annular elongated element can pass through the holes to form a ring, such as... Figure 3H The magnified portion is shown below. Figure 3HEnlarged views A and B illustrate two alternative configurations in which the annular elongated element passes through the hole 71 to form a ring. For some applications, as shown in enlarged view A, the annular elongated element surrounds the outer surface of the helical elongated element and the through hole 71. Alternatively, the helical elongated element defines a groove 45 on its outer surface, and the annular elongated element surrounds the groove 45 and the through hole 71 (so as to be embedded within the groove), as shown in enlarged view B. By embedding the annular elongated element within the groove, the annular elongated element typically does not increase the outer profile of the impeller, and the outer profile of the impeller is defined by the outer surface of the helical elongated element.

[0276] Now refer to Figure 3I , Figure 3J and Figure 3K For some applications, structure 59 is configured to provide a relatively long effective maximum span length (EML), defined as the axial length along which the impeller span is at its maximum. Typically, increasing the effective maximum span length (EML) of the impeller increases the impeller's efficiency (i.e., the flow rate produced by the impeller at a given rotational speed). For some applications, the angle rho formed by the leading edge of the impeller blades relative to the longitudinal axis of the impeller is greater than 45 degrees, for example, between 45 and 70 degrees. By comparison... Figure 3J and Figure 3I It can be observed that, assuming all other things being equal, increasing the angle rho increases the effective maximum span length EML even without increasing the total impeller length. Alternatively, as... Figure 3K As shown, the effective maximum span length (EML) of the impeller is increased by making the impeller longer.

[0277] Now refer to Figure 5A and Figure 5B These figures are schematic diagrams of the impeller 50 and frame 34 of a ventricular assist device 20 in non-radial restraint and radial restraint states, respectively, according to some applications of the invention. During catheter insertion into the subject, the impeller and frame are typically configured in a radial restraint state, while during impeller operation within the left ventricle of the subject, they are configured in a non-radial restraint state. As described above, typically, tube 24 is disposed on at least a portion of the frame and extends proximally from there. However, for illustrative purposes, in Figures 5A-5B The image shows the frame and impeller without tube 24.

[0278] like Figure 5BAs shown, the frame and impeller are typically held in a radially constrained configuration by the delivery duct 143. Typically, in a radially constrained configuration of the impeller, the total length of the impeller is greater than 15 mm (e.g., greater than 20 mm) and / or less than 30 mm (e.g., less than 25 mm), for example, 15 mm–30 mm, or 20 mm–25 mm. More typically, in a non-radially constrained configuration of the impeller, the length of the impeller is greater than 8 mm (e.g., greater than 10 mm) and / or less than 18 mm (e.g., less than 15 mm), for example, 8 mm–18 mm, or 10 mm–15 mm. Even more typically, when the impeller and frame 34 are arranged in a radially constrained configuration (e.g.... Figure 5B As shown), the impeller has an outer diameter of less than 2 mm (e.g., less than 1.6 mm), and the frame has an outer diameter of less than 2.5 mm (e.g., less than 2.1 mm).

[0279] Also refer to Figure 5C It shows a typical support assembly used in a prior art axial-flow impeller-based blood pump. Figure 5C The illustrations are intended to serve as reference points for some applications of the invention described herein. For example... Figure 5C As shown, the support assembly typically includes a radial support (indicated by ellipse 200) and a thrust support (indicated by circle 202). The radial support is configured to reduce the radial movement of the impeller by maintaining the impeller's axis in a given radial position. In response to the impeller pumping blood in a first direction, typically, a force acting on the impeller pushes the impeller to move in the opposite direction. The purpose of the thrust support is to resist this movement of the impeller and maintain the impeller's axial position. Figure 5C In the example shown, in response to the impeller pumping blood in the direction of arrow 204, the impeller is pushed in the direction of arrow 206, and the thrust support resists this movement. Typically, these supports undergo significant heating and wear due to the frictional forces applied to them. Thrust supports typically experience significant heating and wear because the frictional forces applied to them are typically distributed across opposing surfaces, and the contact area between these surfaces is smaller than that for radial supports.

[0280] As described above, typically, the axial shaft 92 passes through the axis of the impeller 50 via the impeller's inner cavity 62. Typically, the proximal bushing 64 of the impeller is connected to the shaft via a connecting element 65, such that the proximal bushing is fixed in axial position relative to the shaft, and the distal bushing 58 of the impeller is slidable relative to the shaft. The axial shaft itself is radially stabilized via a proximal radial support 116 and a distal radial support 118.

[0281] Typically, the connecting portion 31 of the frame 34 is connected to the proximal radial support 116, for example, via a snap-fit ​​connection and / or via welding. Typically, at the distal end of the frame 34, the distal strut joint 33 is placed into a recess defined by the outer surface of the distal radial support 118, the recess being shaped to conform to the shape of the distal strut portion. The proximal end of the distal tip element 107 (which defines the distal tip portion 120) typically holds the distal strut portion in its closed configuration surrounding the outside of the distal radial support 118, as shown. For some applications, the device includes a distal extension 121 extending distally from the distal radial support. Typically, this extension is configured to reinforce the area of ​​the distal tip element that is moved into by the distal end of the shaft 92 (e.g., the axial shaft receiving tube 126 or a portion thereof described below).

[0282] As described above, the axial shaft 92 is radially stabilized via the proximal radial support 116 and the distal radial support 118. Furthermore, the axial shaft radially stabilizes the impeller relative to the inner surface of the frame 34 by passing through the cavity 62 defined by the impeller, such that even relatively small gaps (e.g., gaps as described above) between the outer edges of the impeller blades and the inner surface of the frame 34 are maintained during impeller rotation. For some applications, the axial shaft 92 is made of stainless steel, and the proximal support 116 and / or the distal support 118 are made of hardened steel. Typically, when the impeller and frame are pressed (i.e., radially constrained) for insertion into a subject's body, the distal bushing 58 of the impeller is configured to slide distally along the axial shaft, causing the impeller to become axially elongated while the proximal bushing remains axially fixed relative to the axial shaft. More typically, by sliding the distal bushing on the axial shaft while the proximal bushing remains axially fixed relative to the axial shaft, the impeller changes from its radially constrained configuration to its non-radially constrained configuration, and vice versa. For some applications, the distal bushing 58 of the impeller is connected to the shaft via a connecting element 65, such that the axial position of the distal bushing relative to the shaft is fixed, and the proximal bushing 64 of the impeller is slidable relative to the shaft. See below. Figures 11A-11C Describe this application.

[0283] Typically, the impeller itself is not directly housed within any radial or thrust support. Instead, supports 116 and 118 act as radial supports relative to the axial shaft. Typically, the pump section 27 (and more generally, the ventricular assist device 20) does not include any thrust support configured to be disposed within the subject's body and configured to resist the thrust generated by the rotation of the impeller. For some applications, one or more thrust supports are disposed outside the subject's body (e.g., within the motor unit 23, such as...). Figure 1A , Figure 7 and Figures 8A-8B(as shown), and resistance to the thrust generated by the rotation of the impeller is provided solely by one or more thrust supports disposed outside the subject's body. For some applications, mechanical and / or magnetic elements are configured to hold the impeller within a given axial position range. For example, a magnet (e.g., magnet 82, hereinafter referred to) disposed near the proximal end of the drive cable (e.g., outside the subject's body). Figure 7 (As described) can be configured to apply axial movement to the impeller and / or hold the impeller within a given axial position range.

[0284] Now refer to Figure 6A and Figure 6B These figures are schematic diagrams of a ventricular assist device 20 at various stages of its motion cycle relative to the frame 34 of the ventricular assist device, according to some applications of the invention. For some applications, when the impeller pumps blood through the tube 24 by rotation, the axial shaft 92 (on which the impeller is fixed) is driven to cause the impeller to reciprocate axially within the frame 34 by moving the axial shaft in an axial reciprocating motion, as shown below. Figure 7 Further detailed description. Alternatively or additionally, the impeller and axial shaft are configured to reciprocate axially within the frame 34 in response to forces acting on the impeller, without requiring active drive of the axial shaft to move in a reciprocating manner. Typically, during a subject's cardiac cycle, the pressure gradient between the left ventricle and the aorta changes from approximately zero during ventricular systole (hereinafter referred to as "systole") to a relatively large pressure gradient (e.g., 50 mmHg–70 mmHg) during ventricular diastole (hereinafter referred to as "diastole"). For some applications, due to the increased pressure gradient resisted by the impeller pumping during diastole (and because the drive cable 130 is stretchable), the impeller is pushed distally relative to the frame 34 during diastole compared to its position relative to the frame 34 during systole. Consequently, the axial shaft moves forward because the impeller is connected to it. During systole, the impeller (and consequently the axial shaft) returns to its systolic position. In this way, the axial reciprocating motion of the impeller and axial shaft is generated passively, that is, it is not necessary to actively drive the axial shaft and impeller to undergo this motion. For example, refer to Figure 9 The passive axial reciprocating motion of the impeller will be described in further detail below. Figure 6A The impeller and axial shaft are shown positioned at their typical contraction point, and Figure 6B The impeller and axial shaft are shown in their typical diastolic position.

[0285] In some applications, the portion of the axial shaft in contact with the proximal support 116 and the distal support 118 changes continuously due to its axial reciprocating motion. In some such applications, assuming all else is equal, the frictional force exerted on the axial shaft by the supports is distributed over a larger area of ​​the axial shaft compared to when the axial shaft does not move relative to the supports, thereby reducing wear on the axial shaft. Alternatively or additionally, by reciprocating relative to the supports, the axial shaft removes any residue, such as blood residue, from the interface between the axial shaft and the supports.

[0286] For some applications, when the frame 34 and impeller 50 are in their non-radially constrained configuration (e.g., when the frame and impeller are deployed in the left ventricle), the length of the frame exceeds the length of the impeller by at least 2 mm (e.g., at least 4 mm, or at least 8 mm). Typically, the proximal support 116 and the distal support 118 are each 2 mm to 4 mm in length (e.g., 2 mm to 3 mm). More typically, the impeller and the axial shaft are configured to reciprocate axially within the frame at least along the length of each of the proximal and distal supports, or at least along twice the length of each of these supports. Thus, during the reciprocating axial movement of the axial shaft, the axial shaft is wiped clean on either side of each of the supports.

[0287] For some applications, the range of impeller motion is as follows: Figures 6A-6B As shown, where Figure 6A The impeller is positioned closest to the heart during the cardiac cycle (typically, the impeller is positioned this way during systole), and Figure 6B This indicates the impeller's furthest position during the cardiac cycle (typically, the impeller is positioned this way during diastole). For example... Figure 6A As shown, for some applications, at the closest position to the impeller, the proximal end of the impeller is positioned at position Ip, which is within the proximal conical segment of frame 34. For example... Figure 6B As shown, for some applications, at the most distal position of the impeller, the distal end of the impeller is positioned at position Id, which is at the distal end of the cylindrical segment of frame 34. For the purposes of this application, the entire segment of the frame from Ip to Id can be considered to house the impeller, since this entire segment of the frame typically houses at least a portion of the impeller during at least a portion of the cardiac cycle. Typically, during the entire cardiac cycle, the segment with the largest impeller span is located within the cylindrical portion of frame 34. However, during at least a portion of the cardiac cycle, the proximal portion of the impeller is typically located within the proximal conical segment of the frame.

[0288] Refer again Figure 6A and Figure 6B And also refer to Figure 6C , Figure 6C This is an enlarged schematic diagram of a distal tip element 107 according to some applications of the present invention, comprising an axial shaft receiving tube 126 of a ventricular assist device 20 and a distal tip portion 120. Typically, the distal tip element 107 is a single integrated element comprising both the axial shaft receiving tube 126 and the distal tip portion 120. For some applications, the distal tip element 107 is configured to be flexible, such that the distal tip portion is configured not to cause tissue damage to the subject even if the distal tip portion comes into contact with tissue (e.g., tissue of the left ventricle). For example, the distal tip element 107 may be made of silicone, polyethylene terephthalate (PET), and / or polyether block amide (e.g., It is made of [material name missing]. For some applications, the distal tip portion defines the lumen 122 passing through it. For some such applications, during the insertion of the ventricular assist device into the left ventricle, the guide wire 10 ([material name missing]) is [missing information]. Figure 1B First, the device is inserted into the left ventricle according to, for example, known techniques. Then, the distal tip of the ventricular assist device is guided into the left ventricle by advancing the distal tip portion of the guide wire, which is positioned within the lumen 122. For some applications, a duckbill valve 390 (or a hemostatic valve of a different type) is positioned distal to the lumen 122 of the distal tip portion 120, as described in further detail below.

[0289] Typically, during insertion of the ventricular assist device into the ventricle of a subject, the delivery catheter 143 is positioned on the impeller 50 and frame 34, and the impeller and frame are maintained in their radially constrained configuration. For some applications, during insertion of the delivery catheter into the subject's ventricle, the distal tip element 107 extends distally from the delivery catheter. For some applications, at the proximal end of the distal tip element, the distal tip element has a flared portion 124 that serves as a stop and prevents the delivery catheter from being advanced beyond the flared portion.

[0290] It should be noted that, Figures 6A-6C The external shape of the distal tip portion (and some other figures) is shown as defining a complete ring, wherein the distal end of the distal tip portion (within which the duckbill valve 390 is disposed) spans the more proximal portion of the distal tip portion. Typically, due to the guide wire inserted therethrough (during insertion of the ventricular assist device into the left ventricle), the distal tip portion remains partially extended, even after the guide wire is removed from the distal tip portion. Typically, the partial extension of the distal tip portion is such that when the distal tip portion is positioned in the left ventricle, in the absence of external force acting on the distal tip portion, the distal tip portion does not define a complete ring, for example, as shown in the figures. Figure 1B and Figure 23AAs shown. Other aspects of the shape of the distal tip portion will be described in further detail below.

[0291] Refer again Figure 6C For some applications, the axial shaft receiving tube 126 extends proximally from the distal tip portion 120 of the distal tip element 107. As described above, typically, the axial shaft undergoes axial reciprocating motion during impeller 50 operation. The axial shaft receiving tube 126 defines a cavity 127 configured to receive the axial shaft when it extends beyond the distal support 118. For some applications, the shaft receiving tube defines a stop 128 at its distal end, configured to prevent the axial shaft from being pushed beyond the stop. For some applications, the stop includes a rigid member inserted (e.g., embedded) into the distal end of the shaft receiving tube. Alternatively, the stop includes a shoulder between the cavity 127 of the axial shaft receiving tube and the cavity 122 of the distal tip portion 120. Typically, such a shoulder exists because the cavity 122 of the tip portion 120 is narrower than the cavity 127. This is because the inner cavity 127 is typically configured to receive the axial shaft, while the inner cavity 122 is configured to receive the guide wire 10, and the axial shaft is typically wider than the guide wire 10 because the axial shaft itself is configured to receive the guide wire 10 within the inner cavity 132 of the axial shaft (e.g., Figure 10B and Figure 10C (As shown).

[0292] Typically, during normal impeller operation, the axial shaft does not extend to the stop 128, even when the drive cable 130 ( Figure 7 This is also true when the ventricular assist device 20 is extended to its maximum extent (e.g., during diastole). However, during the retraction of the ventricular assist device 20 from the subject's ventricle, as the delivery catheter is advanced over the impeller 50 and frame 34, the stop 128 is configured to prevent the axial shaft from protruding into the tip portion. In some cases, there is a risk of the drive cable snapping during the advancement of the delivery catheter over the frame and impeller. Without the stop 128, in this situation, the axial shaft might protrude into the tip portion. The stop 128 prevents this from happening, even in the event of drive cable snapping.

[0293] Typically, during the operation of the ventricular assist device and throughout the entire axial reciprocating cycle of the impeller, the impeller is positioned relatively very close to the distal tip. For example, the distance from the impeller to the distal tip can be within the farthest 50% of the tube 24, such as the farthest 30% (or the farthest 20%).

[0294] Now refer to Figure 6DThis is a schematic diagram of an impeller 50 and an axial shaft 92 of a ventricular assist device 20 according to some applications of the present invention, wherein a region of the axial shaft is coated with a coating or covering material 95. As mentioned above, typically, the distal bushing 58 of the impeller is not fixedly connected to the shaft. Also as mentioned above, to reduce hemolysis, it is typically desirable to maintain a constant clearance between the edge of the impeller blades and the tube 24 (and / or liner 39). Therefore, it is typically desirable to reduce impeller vibration. For some applications, the region of the impeller along the axial shaft is stabilized relative to the frame by reducing the clearance between at least one bushing and the impeller (e.g., by substantially filling the gap), in this region, the distal bushing is configured to slide relative to the axial shaft coated to substantially prevent impeller vibration. For example, this region of the axial shaft may be coated with polytetrafluoroethylene (e.g., polytetrafluoroethylene). The impeller may be coated with a diamond-like carbon (DLC) coating, or may be covered with a sleeve (typically a polymer, such as polyester). By substantially filling the gap between the inner surface of the distal bushing 58 and the outer surface of the axial shaft 92, impeller vibration is typically reduced compared to an uncoated area of ​​the axial shaft. For some applications, the gap between the distal bushing and the axial shaft is less than 40 micrometers, for example, less than 30 micrometers, regardless of whether the axial shaft is coated. For some applications, the proximal bushing of the impeller is configured to slide relative to the axial shaft (e.g., as referenced). Figures 11A-11C The aforementioned techniques are applicable to the proximal bushing.

[0295] Now refer to Figure 6E This is a schematic diagram of an impeller 50 and an axial shaft 92 of a ventricular assist device 20 according to some applications of the present invention. The distal bushing 58 of the impeller includes a protrusion 96 projecting from its inner surface, which is configured to slide within a groove 97 defined by the outer surface of the axial shaft. As described above, typically, the distal bushing 58 of the impeller is not fixedly coupled to the shaft. For some applications, when the impeller moves axially relative to the axial shaft, the protrusion 96 and the groove 97 are configured to prevent the distal end of the impeller from rotating relative to the axial shaft. Typically, at the proximal end of the groove 97, the groove 97 defines a stop 98. The stop is configured to prevent the distal bushing from sliding proximally beyond the stop by preventing axial movement of the protrusion 96 beyond the stop. Typically, by preventing the distal bushing from sliding proximally beyond the stop, a minimum length of the impeller is maintained. This, in turn, typically prevents the impeller span from increasing beyond a given maximum span, thus maintaining the clearance between the edges of the impeller blades and the tube 24 (and / or liner 39).

[0296] according to Figures 6A-6EBased on the foregoing description (and the description of the other accompanying drawings), the scope of the invention includes one or more techniques for reducing hemolysis caused by impeller-pumped blood. Typically, a frame 34 surrounding the impeller defines a plurality of cells, and the frame is configured such that, in a non-radial constrained configuration, the frame includes a generally cylindrical portion 38. More typically, the cell width CW of each cell within the cylindrical portion, measured around the circumference of the cylindrical portion, is less than 2 mm (e.g., 1.4 mm–1.6 mm, or 1.6 mm–1.8 mm). For some applications, a liner 39 is at least lining the cylindrical portion of the frame, and the impeller is disposed within the frame such that, in a non-radial constrained configuration, at the location of the greatest impeller span, the impeller is disposed within the cylindrical portion of the frame, such that the gap G between the outer edge of the impeller and the liner is less than 1 mm (e.g., less than 0.4 mm). Typically, the impeller is configured to rotate to pump blood from the left ventricle to the aorta and is stabilized relative to the frame, such that the gap between the outer edge of the impeller and the liner is maintained and remains substantially constant during impeller rotation. Typically, compared to an impeller that is unstable relative to the frame, the impeller is configured to reduce the risk of hemolysis by being stabilized relative to the frame (so that the gap between the outer edge of the impeller and the liner is maintained and remains substantially constant during impeller rotation).

[0297] For some applications, a proximal radial support 116 and a distal radial support 118 are respectively disposed at the proximal and distal ends of the frame, and an axial shaft 92 passes through the proximal and distal radial supports. Typically, the impeller is stabilized relative to the frame by holding the impeller in a radially fixed position relative to the axial shaft, and by the rigidity of the axial shaft. For some applications, the clearance between each axial support and the axial shaft is less than 15 micrometers, for example, between 2 and 13 micrometers. For some applications, the impeller includes bushings 64, 58 disposed around the axial shaft, and at least one of these bushings (e.g., distal bushing 58) is configured to be slidable relative to the axial shaft. For some applications, the impeller is stabilized relative to the frame along a region of the axial shaft in which at least one bushing is configured to be slidable relative to the axial shaft, and this region is coated to substantially prevent impeller vibration by reducing the clearance between at least one bushing and the impeller. For example, this area can be coated with diamond-like carbon, polytetrafluoroethylene, and / or polymer sleeves. For some applications, regardless of whether the axial shaft is coated, the clearance between the distal bushing and the axial shaft is less than 40 micrometers, for example, less than 30 micrometers.

[0298] Now refer to Figure 6F and Figure 6GThese figures are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, wherein the cylindrical portion 38 of the frame 34 tapers gradually from the proximal end to the distal end of the cylindrical portion. As described above, for some applications, the impeller 50 and the axial shaft 92 are configured to reciprocate axially within the frame 34 in response to forces acting on the impeller, without requiring active driving of the axial shaft to move in a manner that allows for axial reciprocating motion. Typically, during a subject's cardiac cycle, the pressure gradient between the left ventricle and the aorta varies from approximately zero during systole to a relatively large pressure gradient (e.g., 50 mmHg–70 mmHg) during diastole. For some applications, due to the increased pressure gradient resisted by the impeller pumping during diastole (and because the drive cable 130 is stretchable), the impeller is pushed distally relative to the frame 34 during diastole compared to its position relative to the frame 34 during systole. Furthermore, the axial shaft moves forward because the impeller is connected to the axial shaft. During the contraction phase, the impeller (and consequently the axial shaft) moves back to its contraction position. In this way, the axial reciprocating motion of the impeller and the axial shaft is generated passively, i.e., it does not require active driving of the axial shaft and impeller to cause them to undergo this motion. Figure 6F The impeller is shown positioned at its typical contraction period location, and Figure 6G The impeller is shown positioned at its typical diastolic position.

[0299] For some applications, because the cylindrical portion of frame 34 tapers from its proximal to distal end, the clearance between the impeller blade edges and the tube 24 (and / or liner 39) is smaller during the diastolic phase than during the systolic phase. Due to this smaller clearance, the impeller typically exhibits higher pumping efficiency during the diastolic phase than during the systolic phase. For some applications, it is desirable to have higher pumping efficiency during the diastolic phase than during the systolic phase because the pressure gradient resisted by the impeller increases during the diastolic phase relative to the systolic phase, as described above.

[0300] Despite Figure 6E and Figure 6F While described, typically the clearance between the impeller blade edges and the tube 24 (and / or liner 39) is constant throughout the entire axial motion cycle of the impeller.

[0301] Now refer to Figure 7 This is a schematic exploded view of the motor unit 23 of a ventricular assist device 20 according to some applications of the present invention. For some applications, the console 21 ( Figure 1AThe computer processor 25, which controls the rotation of the impeller 50, is also configured to control the reciprocating motion of the axial shaft. Typically, both types of motion are generated using the motor unit 23. The scope of the invention includes controlling reciprocating motion at any frequency. For some applications, an indication of a subject's cardiac cycle is detected (e.g., by detecting the subject's ECG), and the reciprocating motion of the axial shaft is synchronized with the subject's cardiac cycle.

[0302] Typically, motor unit 23 includes a motor 74 configured to apply rotational motion to impeller 50 via drive cable 130. As described further below, typically, the motor is magnetically coupled to the drive cable. For some applications, axial motion driver 76 is configured to drive the motor in an axial reciprocating motion, as indicated by double-headed arrow 79. Typically, due to the magnetic coupling between the motor and the drive cable, the motor applies reciprocating motion to the drive cable, which in turn applies that motion to the impeller. As described above and below, for some applications, the drive cable, impeller, and / or axial shaft undergo axial reciprocating motion passively, for example, due to periodic changes in pressure gradients resisted by the impeller pumping blood. Typically, for such applications, motor unit 23 does not include axial motion driver 76.

[0303] In some applications, the magnetic coupling between the motor and the drive cable is as follows: Figure 7 As shown. Figure 7 As shown, a set of drive magnets 77 are coupled to a motor via a drive magnet housing 78. For some applications, the drive magnet housing includes a ring 81 (e.g., a steel ring), and the drive magnets are adhered to the inner surface of the ring. For some applications, as shown, a gasket 85 is adhered to the inner surface of the ring 81 between two drive magnets. A driven magnet 82 is disposed between the drive magnets such that there is axial overlap between the drive and driven magnets. The driven magnet is coupled to a pin 131 that extends beyond the distal end of the driven magnet 82, wherein the pin is coupled to the proximal end of a drive cable 130. For example, the driven magnet may be cylindrical and define a hole through it, and the pin 131 may be adhered to the inner surface of the driven magnet defining the hole. For some applications, the driven magnet is cylindrical, and the magnet includes a north pole and a south pole that are separated from each other along the length of the cylinder by a line 83 that bisects the cylinder, as shown. For some applications, the driven magnet is housed within a cylindrical housing 87. Typically, pin 131 defines the guide wire cavity 133, which will be referred to below. Figures 10B-10C Further detailed description.

[0304] Note that in Figure 7In the illustrated application, the driving magnet is positioned outside the driven magnet. However, the scope of this application includes configurations that reverse the driving and driven magnets (with necessary modifications). For example, the proximal end of the drive cable may be coupled to two or more driven magnets arranged around the driving magnet such that there is axial overlap between the driven and driving magnets.

[0305] As described above, typically, the cleaning system 29 (e.g.) Figure 1A (As shown) Used with ventricular assist device 20. Typically, motor unit 23 includes an inlet port 86 and an outlet port 88 for use with a cleaning system. For some applications, cleaning fluid is continuously or periodically pumped into the ventricular assist device via inlet port 86 and pumped out of the ventricular assist device via outlet port 88. Other aspects of the cleaning system will be described below.

[0306] Typically, magnet 82 and pin 131 are held in an axially fixed position within motor unit 23. Typically, the proximal end of the drive cable is coupled to pin 131 and thus held in an axially fixed position by the pin. Typically, drive cable 130 extends from pin 131 to axial shaft 92, thereby at least partially fixing the axial position of the axial shaft, and consequently fixing the impeller 50. For some applications, the drive cable is somewhat stretchable. For example, the drive cable may be made of stretchable coiled wire. The drive cable typically allows the axial shaft (and consequently the impeller) to present a range of axial positions (becoming more or less stretched by the drive cable), but limits the axial movement of the axial shaft and impeller to a certain range of motion (by holding the proximal end of the drive cable in an axially fixed position, and limiting the stretchability of the drive cable).

[0307] Now refer to Figure 8A and Figure 8B These figures are schematic diagrams of motor unit 23 according to some applications of the present invention. Generally, as... Figure 8A and Figure 8B The motor unit 23 shown is similar to Figure 7 The motor unit shown, unless otherwise specified, is as follows: Figure 8A and Figure 8B The motor unit 23 shown includes and Figure 7 The motor unit 23 shown is a similar component. For some applications, the motor unit includes a radiator 90 configured to dissipate heat generated by the motor. Alternatively or additionally, the motor unit includes a vent 93 configured to further dissipate heat generated by the motor. For some applications, the motor unit includes vibration dampers 94 and 96 configured to dampen vibrations of the motor unit caused by the rotational and / or axial reciprocating motion of components of the ventricular assist device.

[0308] As described above, for some applications, the impeller 50 and the axial shaft 92 are configured to reciprocate axially within the frame 34 in response to forces acting on the impeller, without requiring active driving of the axial shaft to move in a reciprocating manner. Typically, during a subject's cardiac cycle, the pressure gradient between the left ventricle and the aorta changes from approximately zero during systole to a relatively large pressure gradient during diastole (e.g., 50 mmHg–70 mmHg). For some applications, due to the increased pressure gradient resisted by the impeller pumping during diastole (and because the drive cable is stretchable), the impeller is pushed distally relative to the frame 34 during diastole, in contrast to its position relative to the frame 34 during systole. Furthermore, since the impeller is connected to the axial shaft, the axial shaft moves forward. During systole, the impeller (and consequently the axial shaft) returns to its systolic position. In this way, the axial reciprocating motion of the impeller and the axial shaft is generated passively, that is, it is not necessary to actively drive the axial shaft and the impeller to make them undergo this motion.

[0309] Now refer to Figure 9 The figure is a graph showing the change in the length of the drive cable of the ventricular assist device as a function of the pressure gradient resisted by the impeller of the ventricular assist device (as measured in experiments conducted by the inventors of this application). The impeller and drive cable described herein are used to pump a glycerol-based solution through a chamber configured to reproduce the left ventricle and aorta, and the solution has properties similar to blood (e.g., density and viscosity). The pressure gradient resisted by the impeller pumping changes as the volume of fluid disposed within the chamber pumped in by the impeller increases. Simultaneously, the movement of the drive cable is imaged, and the change in the length of the drive cable is determined via machine vision analysis of the images. Figure 9 The graph shown illustrates how the measured drive cable length changes with the pressure gradient. Figure 9 The y-axis of the graph shown represents the elongation of the drive cable when the impeller is stationary; 0 mm represents the length of the drive cable. Note that the graph begins at a pressure gradient of 65 mmHg, and at this pressure, the elongation is negative (approximately -0.25 mm), meaning the drive cable is shorter than its length before the impeller begins to rotate. This is because the drive cable configuration causes it to shorten (compared to its length before the impeller starts pumping) when the impeller first begins pumping, due to the unwinding of the coils within the drive cable. Figure 9 As can be seen in the curve shown, after the initial shortening of the drive cable caused by the aforementioned effect, the drive cable subsequently becomes longer and longer as the pressure gradient increases.

[0310] like Figure 9As shown and described above, typically, in response to changes in pressure resisted by the impeller pumping blood (e.g., the pressure difference between the left ventricle and the aorta), the impeller reciprocates relative to the frame 34. This movement of the impeller, in turn, causes the drive cable 130 to elongate more or less.

[0311] For some applications, during the operation of the ventricular assist device, console 21 ( Figure 1A The computer processor 25 is configured to measure the pressure applied to the impeller (indicating the pressure differential between the left ventricle and the aorta) by measuring the tension in the drive cable 130 and / or the indication of the axial movement of the drive cable. In some applications, based on the measured indications, the computer processor detects events in the subject's cardiac cycle, determines the subject's left ventricular pressure, and / or determines the subject's cardiac afterload. In some applications, the computer processor controls the rotation of the impeller and / or, in response, controls the axial reciprocating motion of the axial shaft.

[0312] Refer again Figure 7 For some applications, the ventricular assist device 20 includes a sensor 84. For example, the sensor may include a Hall sensor disposed within the motor unit 23, such as... Figure 7 As shown. For some applications, the Hall sensor measures changes in the magnetic field generated by one of the magnets to measure the axial movement of the drive cable 130 and, consequently, to determine the pressure resisted by the impeller pump. For example, the internal driven magnet 82 may be axially longer than the external drive magnet 77. Because the inner magnet is longer than the outer magnet, the magnetic field lines emanating from the inner magnet are not transmitted to the outer magnet, and the magnetic flux generated by these field lines, as measured by the Hall sensor, changes due to the drive cable, thus causing axial movement of the inner magnet. During operation, the motor 74 rotates, thereby generating an AC signal in the Hall sensor, typically with a frequency between 200 Hz and 800 Hz. Typically, when the tension in the drive cable changes due to the subject's cardiac cycle, this generates a low-frequency envelope in the signal measured by the Hall sensor, typically with a frequency of 0.5 Hz to 2 Hz. For some applications, a computer processor measures the low-frequency envelope and derives the subject's cardiac cycle from the measured envelope. Note that, typically, the axial motion of the magnet is substantially less than that of the impeller, because the impeller's entire range of motion is not transmitted along the length of the drive cable. However, typically, the axial reciprocating motion of the impeller causes a measurable reciprocating motion of the magnet.

[0313] For some applications, the Hall sensor measurements are initially calibrated such that the change in magnetic flux per unit pressure change resisted by the impeller pump (i.e., the change in pressure gradient between the left ventricle and the aorta per unit change) is known. It is known that, in most subjects, the left ventricular pressure equals the aortic pressure during systole. Therefore, for some applications, the aortic pressure of the subject is measured (e.g., using the method described below). Figures 16A-16D The technique described above, and then the computer processor calculates the subject's left ventricular pressure at a given time based on (a) the measured aortic pressure and (b) the difference between the magnetic flux measured by the Hall sensor at that time and the magnetic flux measured by the Hall sensor during systole (assuming the pressure in the left ventricle is equal to the pressure in the aorta).

[0314] For some applications, techniques similar to those described in the preceding paragraphs are generally used, but instead of utilizing Hall effect sensor measurements, different parameters are measured to determine left ventricular blood pressure at a given time. For example, typically, there is a relationship between the amount of power required to drive the impeller at a given rotational rate and the pressure differential generated by the impeller. Note that a portion of the pressure differential generated by the impeller is used to overcome the pressure gradient resisted by the impeller pumping, and another portion is used to actively pump blood from the left ventricle to the aorta by creating a positive pressure differential between the left ventricle and the aorta. Furthermore, the relationship between these components typically changes during the cardiac cycle. For some applications, calibration measurements are performed such that the relationship between (a) the motor power required to rotate the impeller at a given rotational rate and (b) the pressure differential generated by the impeller is known. For some applications, the aortic pressure of the subject is measured (e.g., using the method described below). Figures 16A-16D The technique described above involves a computer processor calculating the subject's left ventricular pressure at a given time based on (a) measured aortic pressure, (b) the motor power consumption required to rotate the impeller at a given rotational rate at a given time, and (c) a predetermined relationship between the motor power consumption required to rotate the impeller at a given rotational rate and the pressure difference generated by the impeller. For some applications, the technique is performed while maintaining a constant impeller rotational rate. Alternatively or additionally, the impeller rotational rate is varied, and this variation is taken into account in the above calculations.

[0315] Typically, tube 24 has a known cross-sectional area (when the tube is open due to blood flow). For some applications, the flow rate through tube 24 generated by the impeller is determined based on a defined pressure differential generated by the impeller and the known cross-sectional area of ​​the tube. For some applications, this flow rate calculation incorporates calibration parameters to account for factors such as flow resistance, which correspond to the specificity of the ventricular assist device (or type of ventricular assist device) being performed. For some applications, a ventricular pressure-volume loop is derived based on a defined ventricular pressure.

[0316] Now refer to Figure 10A , Figure 10B and Figure 10C These figures are schematic diagrams of the drive cable 130 of a ventricular assist device 20 according to some applications of the present invention. Typically, as described above, the rotational motion of the impeller (applied via an axial shaft) and the axial reciprocating motion of the aforementioned axial shaft are transmitted to the axial shaft via the drive cable. Typically, the drive cable extends from the motor unit 23 (which is typically disposed outside the subject's body) to the proximal end of the axial shaft 92 (e.g., Figure 10C As shown, it illustrates the connection between the distal end of the drive cable and the proximal end of the axial shaft. For some applications, the drive cable includes multiple wires 134 (e.g., Figure 10B As shown), these wires 134 are arranged in a tightly coiled configuration to give the drive cable sufficient strength and flexibility so that a portion of the cable can remain within the aortic arch (corresponding to...). Figure 10A (The portion indicated by the middle arrow 145) while the cable rotates and moves in an axial reciprocating motion. Typically, the drive cable is housed within a first outer tube 140, which is configured to remain stationary while the drive cable undergoes rotation and / or axial reciprocating motion. The first outer tube is configured to effectively act as a support along the length of the drive cable. Typically, the first outer tube is made of a polymer (e.g., polyetheretherketone) configured to be highly fatigue-resistant even under frictional forces generated by the relative movement between the drive cable and the first outer tube. However, since such polymers are typically relatively hard, only thin layers of polymer are typically used in the first outer tube. For some applications, the first outer tube is housed within a second outer tube 142, which is made of a material with greater flexibility than the first outer tube (e.g., nylon and / or polyether block amide), and the thickness of the second outer tube is greater than that of the first outer tube.

[0317] Typically, during insertion of the impeller and cage into the left ventricle, the impeller 50 and frame 34 are held in a radially constrained configuration by the delivery catheter 143. As described above, to allow the impeller and frame to present a non-radially constrained configuration, the delivery catheter is retracted. For some applications, such as Figure 10AAs shown, during operation of the left ventricular device, the delivery catheter is held in the subject's aorta, and the outer tube 142 is positioned inside the delivery catheter. For some applications, a channel 224 is defined between the delivery catheter 143 and the outer tube 142 during operation of the left ventricular device. Note that, for illustrative purposes, Figure 10A The pathway shown is not to scale. Pathway 224 will be described in further detail below. To retract the left ventricular device from the subject, the delivery catheter is advanced over the impeller and frame such that the impeller and frame assume their radially constrained configuration. The catheter is then withdrawn from the subject.

[0318] Reference Figure 10C (It shows a cross-sectional view of the drive cable 130 and the axial shaft 92), typically, the axial shaft and the drive cable define a continuous lumen 132 through which they pass. For some applications, the left ventricular device is guided to the aorta and left ventricle by placing the axial shaft and cable on the guide wire 10 (as described above), such that the guide wire is positioned within the lumen 132. Typically, the guide wire is inserted through a duckbill valve 390 (or other hemostatic valve) located at the distal end of the distal tip portion of the distal tip element 107. The guide wire passes through the guide wire lumen 122 (of the distal tip portion) and then into the lumen 132 defined at that point by the axial shaft. The guide wire then continues through the lumen 132 until the proximal end of the drive cable. The guide wire passes from the proximal end of the drive cable through the guide wire lumen 133 defined by the pin 131, which remains outside the subject's body even after the distal end of the ventricular assist device 20 has been inserted into the subject's left ventricle. Typically, when the distal end of the ventricular assist device is positioned inside the left ventricle of the subject, the guide wire is retracted from the subject's body by pulling the guide wire out of the proximal end of the guide wire lumen 133. Subsequently, the axial position of the driven magnet 82 (with pin 131 disposed therein) is fixed so that it is positioned between the drive magnets 77, as... Figure 7 As shown. For example, a portion of the driven magnet in motor unit 23 can be secured using locking element 150 (such as...). Figure 13B As shown, a portion of the drive magnet 77 is connected to the motor unit.

[0319] For some applications, by using the inner cavity 132 of the axial shaft and cable in the manner described above, it is not necessary to provide additional guide wires for use during insertion of the left ventricular assist device 20. For some applications, the outer diameter of the axial shaft and cable is each greater than 0.6 mm (e.g., greater than 0.8 mm) and / or less than 1.2 mm (e.g., less than 1 mm), for example, 0.6 mm–1.2 mm, or 0.8 mm–1 mm. For some applications, the diameter of the inner cavity 132 defined by the shaft and cable is greater than 0.3 mm (e.g., greater than 0.4 mm), and / or less than 0.7 mm (e.g., less than 0.6 mm), for example, 0.3 mm–0.7 mm or 0.4 mm–0.6 mm. For some applications, the total length of the drive cable 130 is greater than 1 m (e.g., greater than 1.1 m), and / or less than 1.4 m (e.g., less than 1.3 m), for example, 1 m–1.4 m, or 1.1 m–1.3 m. Typically, the diameters of the guide wire cavity 122 and the guide wire cavity 133 are approximately similar to the diameter of the cavity 132.

[0320] Now refer to Figure 10D , Figure 10E and Figure 10F These figures are schematic diagrams of various steps in a technique for connecting a drive cable 130 to an axial shaft 92 using a butt-welding sleeve 160 according to some applications of the invention. Typically, the butt-welding sleeve defines a window 162 and a helical groove 164. For some applications, the axial shaft 92 is inserted into a first end of the butt-welding sleeve such that the proximal end of the axial shaft 92 is visible at a given location in the window 162, for example, at the midpoint across the width of the window. Figures 10D to 10E The transition is shown. Subsequently, the drive cable 130 is inserted into the other end of the butt-welding sleeve until the distal end of the drive cable is also positioned at a given location on the window 162 (e.g., at the midpoint across the window width) and typically contacts the proximal end of the axial shaft, as shown. Figure 10E and Figure 10F The transition is shown.

[0321] Note that the order in which the axial shaft and drive cable are inserted into the butt-welded outer sleeve 160 can be the reverse of the order shown. That is, the drive cable can be inserted first, followed by the axial shaft. It should also be noted that, for illustrative purposes, the drive cable is... Figures 10D-10F The diagram shows a tube. However, drive cables typically consist of multiple coiled wires, for example, such as... Figure 10B As shown.

[0322] Typically, once both the axial shaft and the drive cable have been inserted into the welding sleeve 160, multiple welding rings 166 are welded to the welding sleeve. Typically, one ring is welded at a given location on the window 162, for example, at the midpoint across the width of the window. More typically, additional rings are welded on either side of the window 162, but at a location separated from the end of the welding sleeve. In this way, the additional welding rings weld the welding sleeve to the axial shaft and the drive cable, rather than welding the additional welding rings directly to the outer surfaces of the axial shaft and the drive cable. For some applications, this method results in less strain on the welding rings compared to welding the additional welding rings at the ends of the welding sleeve, thus allowing the additional welding rings to be directly welded to the outer surfaces of the axial shaft and the drive cable. Typically, the welding rings are welded to such a depth that the welding sleeve is welded to the axial shaft and the drive cable without reducing the diameter of the guide cavity 132. As shown, typically, the drive cable is inserted into a soldering sleeve such that a spiral groove is positioned around the drive cable. Typically, the spiral groove provides flexibility to the portion of the soldering sleeve positioned on the drive cable 130.

[0323] For some applications, a technique substantially similar to that described for welding the distal end of drive cable 130 to axial shaft 92 (with necessary modifications) is used for welding the proximal end of drive cable to pin 131 (see above). Figure 7 (Description). For some applications, the drive cable includes sections with corresponding characteristics (e.g., a corresponding number of wires in a coiled wire assembly comprising multiple sections of the drive cable). For some such applications, a technique substantially similar to (with necessary modifications) described for welding the distal end of the drive cable 130 to the axial shaft 92 is used to weld the various sections of the drive cable to each other.

[0324] For some applications, certain features of the butt-welded outer sleeve 160 and the techniques used therewith are implemented in the absence of other features. For example, the butt-welded outer sleeve may include a window, and the weld ring may be welded in the manner described above even without the spiral groove.

[0325] Now refer to Figure 11A and Figure 11BThese figures are schematic diagrams of an impeller 50 according to some applications of the invention, wherein the impeller is coupled to an axial shaft 92 at its distal end and not at its proximal end. As described above, typically, the axial shaft 92 passes through the axis of the impeller 50 via the impeller's inner cavity 62. For some applications, the distal bushing 58 of the impeller is coupled to the shaft via a connecting element 65, such that the axial position of the distal bushing relative to the axial shaft is fixed, and the proximal bushing 64 of the impeller is slidable relative to the axial shaft. The axial shaft itself is radially stabilized via a proximal radial support 116 and a distal radial support 118. As described above, the proximal and distal ends of the frame 34 are rigidly coupled to the proximal and distal supports. Furthermore, the axial shaft, by passing through the cavity 62 defined by the impeller, radially stabilizes the impeller relative to the inner surface of the frame 34, such that a relatively small clearance (e.g., the clearance as described above) is maintained between the outer edge of the impeller blades and the inner surface of the frame 34 even during impeller rotation. For this application, typically, when the impeller and frame are pressed (i.e., radially constrained) for insertion into a subject's body, the proximal bushing 64 of the impeller is configured to slide distally along the axial shaft, causing the impeller to become axially elongated, while the distal bushing remains axially fixed relative to the axial shaft. More generally, by sliding the proximal bushing on the axial shaft while the distal bushing remains axially fixed relative to the axial shaft, the impeller changes from its radially constrained configuration to its non-radially constrained configuration, and vice versa.

[0326] Now refer to Figure 11C This is a schematic diagram of a first connecting portion 170A and a second connecting portion 170B according to some applications of the present invention, wherein the first connecting portion 170A and the second connecting portion 170B facilitate [something] independently of other components of the frame 34. Figures 11A-11B The impeller is press-fitted. The first part 170A and the second part 170B are configured to engage with each other. The first part is mounted on the impeller, while the second part is attached to the frame 34 and / or the proximal support 116. See again... Figure 11A and Figure 11B For some applications, before crimping the frame 34, the impeller is radially constrained by engaging portions 170A and 170B together and axially elongating the impeller to constrain it radially. The frame 34 is then crimped. Typically, when the impeller and frame are positioned in the left ventricle of a subject, the first and second connecting portions are separated from each other, allowing the proximal end of the impeller to move relative to the frame 34 and the proximal support 116.

[0327] Now refer to Figure 12A It shows that when the impeller is like Figures 11A-11BThe graph shows the relationship between the pressure gradient resisted by the impeller pump and the impeller pitch in the configuration shown. As shown, since the proximal end of the impeller is slippery, the impeller pitch decreases as the pressure gradient resisted by the impeller pump increases, because the impeller blades are axially compressed by the pressure resisted by the impeller pump. See also... Figure 12B This is a graph showing the pressure-flow rate curves of impellers with corresponding pitches as described herein. Curve C1 corresponds to an impeller with a relatively small pitch, C2 to an impeller with a medium pitch, and C3 to an impeller with a relatively large pitch. As shown, assuming all other things being equal, the smaller the impeller pitch, the larger the gradient of the pressure-flow rate curve. Furthermore, assuming all other things being equal, at relatively high pressure gradients, impellers with smaller pitches produce a larger flow rate than impellers with larger pitches, while at relatively low pressure gradients, impellers with larger pitches produce a larger flow rate than impellers with smaller pitches. Figures 12A-12B For some applications, because the impeller is coupled to an axial shaft at its distal end and can slide relative to the axial shaft at its proximal end, the impeller pitch decreases as the pressure gradient the impeller pumps increases. Therefore, at higher pressure gradients (typically where a smaller pitch produces a larger flow rate), the impeller has a smaller pitch, while at lower pressure gradients (typically where a larger pitch produces a larger flow rate), the impeller has a larger pitch.

[0328] Reference Figure 12B The curves shown, and regarding the impeller typically configured in the context of this application (i.e., the proximal support is connected to the axial shaft, but not in...), Figures 11A-11B As shown in the figure, it is typically desirable for an impeller to have the following characteristics:

[0329] 1) At rotational speeds less than 20,000 RPM (e.g., less than 19,000 RPM), when pumping against a pressure gradient of 100 mmHg–120 mmHg, the impeller provides positive flow or at least zero flow. Thus, even if there is abnormally high back pressure from the aorta to the left ventricle, no blood flows in this direction.

[0330] 2) At rotational speeds less than 20,000 RPM (e.g., less than 19,000 RPM), when pumping against a pressure gradient greater than 50 mmHg (e.g., greater than 60 mmHg), such as 50 mmHg–70 mmHg, the impeller provides a flow rate greater than 3.5 L / min (e.g., greater than 4.5 L / min), such as 3.5 L / min–5 L / min. Under normal physiological conditions, the pressure gradient between the left ventricle and aorta during diastole is within the above range, and the described flow rate is required even during diastole.

[0331] As shown in the curves of 12B, an impeller with a smaller pitch (corresponding to curve C1) is preferred to provide the first feature, but an impeller with a larger pitch (corresponding to curve C3) is preferred to provide the second feature. In light of this background, the inventors of this application have discovered that, in order to optimally satisfy both the first and second features, it is typically desirable for the impeller to have a pitch such that, when the impeller is in its non-radially constrained configuration, the helical elongated elements of the impeller (and therefore the blades of the impeller) undergo a full 360-degree rotation (or, if they are long enough, will undergo a full rotation) over an axial length greater than 8 mm (e.g., greater than 9 mm) and / or less than 14 mm (e.g., less than 13 mm), such as 8 mm–14 mm, 9 mm–13 mm, or 10 mm–12 mm. Typically, when the impeller has the pitch described above, and at a rotational speed of less than 20,000 RPM (e.g., less than 19,000 RPM), the impeller provides zero or positive flow rate at a pressure gradient greater than 100 mmHg (e.g., greater than 110 mmHg), and provides flow rates greater than 3 L / min (e.g., greater than 4.5 L / min), or for example, 3.5 L / min to 5 L / min, at a pressure gradient greater than 50 mmHg (e.g., greater than 60 mmHg), such as 50 mmHg-70 mmHg. Typically, when the impeller is in its non-radial constrained configuration, the impeller is configured to provide the aforementioned flow rates by means of an impeller with a maximum diameter greater than 7 mm (e.g., greater than 8 mm).

[0332] For some applications, at least when the impeller is in a non-radially constrained configuration, the pitch of the helical elongated element 52 of the impeller (and therefore the blades of the impeller) varies along the length of the helical elongated element. Typically, for such applications, the pitch increases from the distal end of the impeller (i.e., the end inserted further into the subject's body, and which is upstream relative to the direction of antegrade blood flow) to the proximal end of the impeller (i.e., the end downstream relative to the direction of antegrade blood flow), such that the pitch increases in the direction of blood flow. Typically, the blood flow velocity increases along the impeller and in the direction of blood flow. Therefore, the pitch increases in the direction of blood flow, thereby further accelerating the blood.

[0333] Now refer to Figure 13A , Figure 13B and Figure 13C These figures are schematic diagrams of the process for cleaning the drive cable 130 of a ventricular assist device 20 according to some applications of the present invention. For some applications, as described above, the axial shaft 92 and cable 130 are surrounded by a first outer tube 140 and a second outer tube 142 proximal to the proximal support 116. Typically, both the first and second outer tubes remain stationary during drive cable rotation. For some applications, the cleaning system 29 (e.g.) Figure 1A (As shown) via inlet port 86 and outlet port 88 (in) Figure 7 , Figure 8A , Figure 8B , Figure 13B and Figure 13C (As shown) Control the flow of the cleaning fluid (e.g., a fluid containing glucose or dextrose). The fluid is configured to remove air from the space between the drive cable and the outer tube, and / or reduce the friction between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable), and / or reduce the friction between the axial shaft 92 and the proximal support 116 and / or the distal support 118.

[0334] Reference Figure 13A For some applications, the cleaning fluid is pumped between the first and second outer tubes, and an opening 146 is present in the first outer tube near the proximal support. For some applications, the cleaning fluid flows through the opening 146 between the first outer tube 140 and the drive cable 130, such as... Figure 13A The cleaning fluid flow is indicated by arrow 148. In this way, the interface between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during the rotation of the drive cable) is cleaned. For some applications, some cleaning fluid additionally flows to the interface between the axial shaft and the proximal support 116, thereby cleaning this interface (and / or reducing friction at this interface), such as... Figure 13A The flow of the cleaning fluid is indicated by arrow 149. Typically, the flow of the cleaning fluid in the direction of arrow 149 also prevents blood from flowing into the interface between the axial shaft and the proximal support.

[0335] As mentioned above (see reference) Figure 10B The drive cable typically comprises multiple coiled wires. In some applications, cleaning fluid enters the cavity 132 defined by the drive cable through gaps in the coiled wires. Once the cleaning fluid is positioned within the cavity 132, it flows in both proximal and distal directions, such as... Figure 13A As shown by arrow 151. Figure 13A As indicated by arrow 152, the cleaning fluid flowing distally typically exits the distal end of cavity 132 and flows toward cavity 122 defined by the distal tip portion. At the end of the distal tip portion, a duckbill valve 390 typically prevents the cleaning fluid from exiting the distal tip portion. Therefore, some of the cleaning fluid typically flows toward the interface between the axial shaft and the distal support 118, thereby cleaning the interface (and / or reducing friction at the interface), such as... Figure 13A The cleaning fluid flow is indicated by arrow 154. Typically, the flow of cleaning fluid in the direction of arrow 154 also prevents blood from flowing into the interface between the axial shaft and the distal support.

[0336] As described above, once the cleaning fluid is placed within the inner cavity 132, the cleaning fluid flows in both the proximal and distal directions, such as... Figure 13A As shown by arrow 151. Now refer to... Figure 13B Typically, at the proximal end of the ventricular assist device 20, the cleaning fluid flows out of the proximal end of the lumen 132 in the direction of arrow 156, and subsequently out of the proximal end of the lumen 133 defined by pin 131. In some applications, the cleaning fluid then flows in the direction of arrow 157 and around the driven magnet to reduce friction on the driven magnet. In some applications, the cleaning fluid then flows out of the outlet port 88 in the direction of arrow 158. Typically, the cleaning fluid is then disposed of. Alternatively, the cleaning fluid is pumped back into the device via the inlet port 86.

[0337] Referring to the above description of the cleaning process typically used with the ventricular assist device 20, it should be noted that the guideline cavities 122, 132, and 133 (as described above, which were previously used to facilitate insertion of the device onto the guideline 10) typically serve as flow channels for cleaning fluid during use of the ventricular assist device.

[0338] Now refer to Figure 13C For some applications, the ventricular assist device includes an additional cleaning fluid inlet port 89, typically used to pump cleaning fluid into a channel 224 between the delivery catheter 143 and the outer tubing 142. For some applications, the cleaning fluid is pumped into this channel at a sufficiently low pressure to allow aortic blood pressure to still be detected via this channel, as described in further detail below. For some applications, instead of continuously pumping cleaning fluid into channel 224, fluid is pumped into the channel periodically to flush it. For some applications, port 89 and channel 224 are used for aortic pressure sensing, as described in further detail below.

[0339] Now refer to Figure 13D This is a schematic diagram of a ventricular assist device 20 according to some applications of the present invention, which includes an inflatable portion 153 (e.g., a balloon) at its distal tip, the inflatable portion being configured to expand by fluid for cleaning the drive cables of the device. As described above, refer to... Figure 13AFor some applications, the cleaning fluid is pumped through a cavity 132 defined by the drive cable 130 and the axial shaft 92, such that at least some fluid flows all the way to the distal end of the axial shaft. Typically, for such applications, the cleaning fluid continues to flow into the cavity 122 of the distal tip portion 120. For some applications, an expandable portion 153 is disposed around the distal tip portion, and an opening 155 exists between the cavity 122 and the interior of the expandable portion. The expandable portion expands due to the cleaning fluid entering the interior of the expandable portion via the opening 155. For some applications, the expansion of the expandable portion is controlled by controlling the pressure at which the cleaning fluid is pumped into the ventricular assist device 20.

[0340] Note that, according to some applications of the present invention, such as Figure 13D (and for example) Figure 16A , Figure 16B , Figure 16E , Figure 17D , Figure 30 and Figure 31 The shape of the distal tip element 107 shown is generally as described in Tuval's US 2019 / 0209758, which is incorporated herein by reference. The scope of the invention includes combining the apparatus and methods described with respect to any of the drawings with any shape of the distal tip element described herein. It should also be noted that some applications according to the invention, such as... Figure 13D The configuration of frame 34 shown is generally as described in Tuval's US 2019 / 0209758, which is incorporated herein by reference. The scope of the invention includes combining the apparatus and methods described with respect to any of the drawings with any shape of the distal tip portion and / or the configuration of frame 34 described herein.

[0341] Reference Figure 13EFor some applications, as an alternative to pumping a cleaning fluid through the ventricular assist device throughout its operation, fluid 147 is initially released into the space between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during drive cable rotation), such that the fluid fills the space between the drive cable and the outer tube 140, as well as the inner cavity 132. Then, typically, throughout the operation of the ventricular assist device, the fluid is maintained in place between the drive cable and the outer tube 140, and within the inner cavity 132. The fluid is configured to remove air from the space between the drive cable and the outer tube, and / or reduce friction between the drive cable 130 (which rotates) and the outer tube 140 (which remains stationary during drive cable rotation), and / or reduce friction between the axial shaft and the proximal support 116 and / or the distal support 118. For some applications, the fluid is also configured to fill the space between tube 140 and tube 142, for example, by passing through an orifice defined by tube 140. For some such applications, heat-conducting elements are placed inside a first outer tube and / or a second outer tube to dissipate heat from areas where a large amount of heat is generated by friction.

[0342] For some applications, the fluid has a relatively high viscosity, such as greater than 100 mPa·s (e.g., greater than 500 mPa·s), or a viscosity between 100 mPa·s and 1000 mPa·s, so that the fluid remains substantially in place during operation of the ventricular assist device. For example, petrolatum oil and / or ultrasound coupling gel can be used as the fluid. For some applications, the fluid is initially heated to temporarily reduce its viscosity in order to pump it to the distal end of the ventricular assist device.

[0343] Now refer to Figure 14A , Figure 14B and Figure 14C These figures are schematic diagrams of a stator 250 according to some applications of the invention, the stator 250 being configured to be disposed within the tube 24 of the ventricular assist device 20, proximal to the frame 34 and impeller 50. For some applications, the stator consists of a frame 252 coupled to an outer tube 142 and a flexible material 254 coupled to the frame (e.g., polyurethane, polyester, silicone, polyethylene terephthalate (PET) and / or polyether block amide). The stator is typically formed to define a plurality of curved protrusions 256 (e.g., more than two and / or fewer than eight curved protrusions) extending radially from the outer tube 142 when the device 20 is in a non-radially constrained configuration. The curvature of the curved protrusions is typically opposite to the direction of rotation of the impeller. The stator is typically configured to reduce the rotational flow component of the blood flow before the blood flows from the outlet opening 109 of the tube 24. For some applications, the protrusions of the stator 250 are not curved.

[0344] Typically, during insertion of tube 24 into the left ventricle, the curved protrusions of the stator are radially constrained by the delivery catheter 143. Upon release from the delivery catheter, the curved protrusions are configured to automatically present their curved configuration.

[0345] Now refer to Figure 15A , Figure 15B , Figure 15C , Figure 15D and Figure 15E These figures are schematic diagrams of a stator 260 according to some applications of the invention, the stator 260 being defined by a tube 24 of a ventricular assist device 20. Typically, the stator 260 is defined by a portion of the tube 24 disposed proximally relative to the frame 34 and the impeller 50, and is configured to reduce the rotational flow component of the blood flow before blood flows from the outlet opening 109 of the tube 24. For some applications, the stator 260 comprises one or more curved bands 262 that bend within the tube 24 around an outer tube 142, such as... Figure 15A As shown. Alternatively or additionally, the stator 260 includes a portion 266 of the tube 24 that is twisted such that the tube wall itself defines folds that reduce the rotational flow component of the blood flow before the blood flows from the outlet opening 109 of the tube 24, as Figure 15B As shown.

[0346] For some applications, along a portion of the tube 24 between the proximal end of the frame 34 and the outlet opening 109, the tube is divided into multiple compartments 267 by a plurality of curved strips 262, such that the compartments define a spiral wound along the length of that portion of the tube, as... Figure 15C As shown. Alternatively, as Figure 15D As shown, along a portion of tube 24 between the proximal end of frame 34 and outlet opening 109, the tube is divided into multiple compartments 269 by multiple strips 264 parallel to the longitudinal axis of tube 24. For some applications, within the portion of tube 24 between the proximal end of frame 34 and outlet opening 109, tube 24 includes multiple helical tubes 268 configured to function as stators 260. For some applications, as shown, the helical tubes are intertwined. Typically, Figure 15A , Figure 15B , Figure 15C , Figure 15D and Figure 15E Each example of the stator 260 shown is configured to reduce the rotational flow component of the blood flow before the blood flows from the outlet opening 109 of the tube 24.

[0347] Now refer to Figure 16A and Figure 16BThese figures are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, the ventricular assist device including one or more ventricular blood pressure measuring tubes 220. As described above, typically, the ventricular assist device includes a tube 24 passing through the aortic valve of a subject, such that the proximal end of the tube is disposed within the subject's aorta, and the distal end of the tube is disposed within the subject's left ventricle. Typically, a blood pump (which typically includes an impeller 50) is disposed within the tube 24, within the subject's left ventricle, and is configured to pump blood from the left ventricle into the subject's aorta through the tube 24. For some applications, the ventricular blood pressure measuring tube 220 is configured to extend at least to the outer surface 212 of the tube 24, such that an opening 214 at the distal end of the blood pressure measuring tube is in direct fluid communication with the subject's blood flow outside the tube 24. Typically, the opening 214 is configured within the subject's left ventricle, proximal to the blood pump (e.g., proximal to the impeller 50). Pressure sensor 216 (in Figure 1A (Illustrated schematically) Blood pressure is measured within the ventricular blood pressure measuring tube. Typically, the pressure sensor measures the subject's blood pressure (i.e., left ventricular blood pressure) outside the tube 24 by measuring the blood pressure within the left ventricular blood pressure measuring tube. Typically, the blood pressure measuring tube 220 extends from outside the subject to an opening 214 at the distal end of the tube, and the pressure sensor 216 is positioned towards the proximal end of the tube, for example, outside the subject. For some applications, a computer processor 25 ( Figure 1A It receives the measured blood pressure reading and controls the blood pumping performed by the impeller in response to the measured blood pressure.

[0348] For some applications, ventricular assist devices include two or more such ventricular blood pressure measuring tubes 220, for example, such as Figure 16A and Figure 16B As shown. For some applications, based on the blood pressure measured in each left ventricular blood pressure measuring tube, the computer processor 25 determines whether the opening of one of the two or more ventricular blood pressure measuring tubes is blocked. For example, this may occur due to the opening coming into contact with the ventricular septum wall and / or different ventricular portions. Typically, in response to determining that the opening of one of the two or more ventricular blood pressure measuring tubes is blocked, the computer processor determines the subject's left ventricular pressure based on the blood pressure measured in another of the two or more ventricular blood pressure measuring tubes.

[0349] Reference Figure 16AAs described above, for some applications, the drive cable 130 extends from a motor outside the subject's body to an axial shaft 92 disposed on an impeller 50. Typically, the drive cable is disposed within an outer tube 142. For some applications, the drive cable is disposed within a first outer tube 140 and a second outer tube 142, as described above. For some applications, at least one aortic blood pressure measuring tube 222 is used to measure aortic blood pressure, the aortic blood pressure measuring tube 222 defining an opening 219 in the outer tube 142 at its distal end. The aortic blood pressure measuring tube is configured to extend from outside the subject's body to the outer surface of the outer tube 142 within the subject's aorta, such that the opening at the distal end of the aortic blood pressure measuring tube is in direct fluid communication with the subject's aortic blood flow. The blood pressure sensor 216 is configured to measure the subject's aortic blood pressure by measuring the blood pressure within the aortic blood pressure measuring tube.

[0350] For some applications, one or more ventricular blood pressure measuring tubes 220 and / or one or more aortic blood pressure measuring tubes 222 are disposed within the outer tube 142, surrounding the drive cable. For some applications, portions of one or more blood pressure measuring tubes are defined by the wall of the outer tube 142, such as... Figure 16A and Figure 16B The cross-section is shown. For some applications, the blood pressure measuring tube within the outer tube 142 has an elliptical cross-section (as shown). Typically, this increases the cross-sectional area of ​​the tube compared to the case with a circular cross-section. Typically, the tube has a circular cross-section within the distal portion of each ventricular blood pressure measuring tube 220 (which extends to the opening 214). For some applications, the diameter of the distal portion of the tube is greater than 0.2 mm and / or less than 0.5 mm (e.g., 0.2 mm–0.5 mm).

[0351] like Figure 16A and Figure 16B As shown, for some applications, the outer tube 142 defines a groove 215 in a portion of the outer surface of the outer tube that is configured to be disposed within the tube 24. Typically, during insertion of the ventricular assist device into a subject, a portion of the ventricular blood pressure measuring tube 220 extending from within the tube 24 to at least the outer surface of the tube 24 is configured to be disposed within the groove, such that this portion of the ventricular blood pressure measuring tube does not protrude from the outer surface of the outer tube.

[0352] Now refer to Figure 16C and Figure 16D These figures are schematic diagrams of a ventricular assist device 20 according to some applications of the invention, which has an aortic blood pressure measurement channel 224 within a delivery catheter 143. For some applications, during operation of the ventricular assist device, the channel 224 is defined between the delivery catheter 143 and the outer tube 142, extending from the distal end of the delivery catheter to the proximal end. For example, Figure 10AThe gap between the outer side of the outer tube 142 and the inner side of the delivery conduit 143 is shown; this gap can serve as the aforementioned channel. Note that, for illustrative purposes, Figure 10A The proportions of the channels shown are not proportional. Typically, during operation of a ventricular assist device, the distal end of the delivery catheter is positioned within the subject's aorta, and the proximal end is positioned outside the subject's body. Therefore, by sensing the pressure within the channel between the delivery catheter 143 and the external catheter 142, the blood pressure sensor 216 (which in...) Figure 1A As shown in the diagram, and typically positioned outside the subject's body, the pressure sensor can detect aortic pressure. For some applications, the pressure sensor is located via port 89 (e.g., ...). Figure 13C (As shown) Sensing aortic pressure. As described above, refer to... Figure 13C The cleaning fluid is typically pumped into the channel between the delivery catheter 143 and the outer tube 142. For some applications, the cleaning fluid is pumped into this channel at a sufficiently low pressure so that aortic blood pressure can still be monitored via this channel in the manner described above.

[0353] For some applications, a septum 240 is positioned between the outer catheter 142 and the delivery catheter 143 along at least the distal portion of the delivery catheter 143 to fill the gap between the outer catheter and the delivery catheter. For some applications, the septum is configured to prevent debris, emboli, and / or other substances from flowing out of the distal end of the delivery catheter, where they might flow into the carotid artery 241. For some applications, the delivery catheter defines a side hole 242 exposed to aortic blood flow. For some such applications, the septum is not positioned between the delivery catheter and the outer catheter near the hole 242, such as... Figure 16C As shown. Therefore, near orifice 242, channel 224 is defined between the delivery catheter and outer tube 142, such that the subject's aortic blood pressure is detected via channel 224 in the manner described above. Alternatively, near orifice 242, a septum is disposed between the delivery catheter and outer tube, but the septum defines channel 224 extending from the orifice to the proximal end of the delivery catheter, as shown. Figure 16D As shown. Typically, the subject's aortic blood pressure is detected via channel 224 in the manner described above (e.g., via port 89).

[0354] Now refer to Figure 16EThis is a schematic diagram of a ventricular assist device 20 according to some applications of the invention, which includes one or more blood pressure measuring sensors 270 disposed on the outer surface of a tube 24. For some applications, a wire 272 is used to perform techniques substantially similar to those described for a reference ventricular blood pressure measuring tube 220, extending along the blood pump tube 24 (and typically extending outside the subject's body) to the outer surface of the tube 24. The blood pressure measuring sensors 270 are disposed at the tips of the wires in electrical communication with the subject's blood flow outside the tube 24. The subject's blood pressure (e.g., the subject's ventricular blood pressure and / or the subject's aortic blood pressure) is measured outside the tube 24 by detecting electrical parameters using the sensors. For some applications, the wire 272 and / or the sensor 270 are printed on the outer surface of the tube 24.

[0355] For some applications, sensor 270 is configured to perform conductance measurements. For some applications, the conductance sensor is disposed within tube 24 (rather than on the outer surface of tube 24), but is configured to sense conductance using a frequency substantially unaffected by tube 24. For some applications, an additional conductance sensor is disposed on the left ventricular assist device, for example, on the distal tip element 107. For some such applications, computer processor 25 ( Figure 1A A current is applied between the distal electrode and the proximal electrode, typically positioned near the apex of the heart and the proximal electrode typically positioned above the aortic valve. The conductance of the current between each pair of electrodes is then measured by a computer processor. For some applications, the application of current and conductance measurement are performed using a technique substantially similar to that described in Cassidy et al.'s article, "The Conductance Volume Catheter Technique for Measurement of Left Ventricular Volume in Young Piglets" (Pediatric Research, Vol. 31, No. 1, 1992, pp. 85-90). For some applications, the computer processor is configured to derive the subject's real-time left ventricular pressure-volume loop based on the conductance measurement. For some applications, the computer processor controls the impeller rotation rate in response to the derived pressure-volume loop.

[0356] For some applications, the subject's ventricular blood pressure is derived from conductance measurements. For some such applications, the subject's aortic blood pressure is measured (e.g., as described above). The subject's left ventricular pressure is derived by measuring conductance measurements during the subject's cardiac cycle and determining the difference between the left ventricular pressure and aortic pressure at any given point during the cardiac cycle based on previously calibrated conductance measurements using the left ventricular / aortic pressure gradient. For some applications, the computer processor is configured to calculate the first derivative of the left ventricular pressure measurement. Typically, this change represents the rate of change of left ventricular pressure, which is itself an important clinical parameter. Note that the first derivative of left ventricular pressure is typically unaffected by changes in aortic pressure because the aortic pressure curve is relatively flat as the left ventricular pressure curve undergoes clinically significant changes.

[0357] Now refer to Figure 17A , Figure 17B , Figure 17C and Figure 17D These figures are schematic diagrams of the outer tube 142 of a ventricular assist device 20 according to some applications of the present invention, the outer tube including a pitot tube 225 configured to measure blood flow through the tube 24 of the device. Figures 17A-17D A portion of the outer tube 142 shown is typically disposed within the tube 24. For some applications, the flow obstruction 226 (typically funnel-shaped) is configured to create a stagnation area near the stagnation pressure interface 227. For some applications, such as... Figure 17A As shown, a flow straightener 228 is added to the outer surface of pipe 142 to remove any turbulent components in the flow (which do not contribute to the axial flow velocity). Alternatively, as... Figure 17B As shown, the stagnation pressure port is positioned sufficiently close within the funnel-shaped flow barrier 226 such that the flow barrier itself serves to remove turbulent components from the flow before the blood reaches the stagnation pressure port. For some applications, the stagnation pressure port includes a short tube 233 that protrudes from the outer tube 142 within the funnel-shaped flow barrier 226, such that the opening of the short tube 233 faces the direction of axial blood flow through the tube 24, as shown in the example. Figure 17C As shown. The outer tube 142 also defines an opening 219, which serves as a static pressure port 229. The pressure within the stagnant pressure port 227 and the static pressure port 229 is measured using a pressure sensor, for example, as referenced above. Figures 16A-16D The pressure sensor described above is installed outside the subject's body.

[0358] In some applications, the flow rate through pipe 24 is calculated based on pressure measurements. For example, the flow rate through pipe 24 can be calculated using the following equation:

[0359]

[0360] in:

[0361] Q is the flow rate through pipe 24.

[0362] C is a calibration constant determined empirically and taking into account factors such as impeller speed and the geometry of pressure ports 227 and 229.

[0363] A is the cross-sectional area of ​​pipe 24 (excluding the area occupied by outer pipe 142).

[0364] ΔP is the difference between the stagnation pressure (measured via pressure port 227) and the static pressure (measured via pressure port 229).

[0365] ρ is the fluid density of blood.

[0366] Reference Figure 17D For some applications, the region 230 defined by the pitot tube 225 of tube 24 narrows relative to the rest of the cylindrical portion of tube 24. For some applications, this narrowing facilitates more precise measurements using the pitot tube. For some applications, the narrow region 230 of tube 24 is configured to be placed within the aortic valve of the subject. Typically, the narrowing of the tube at region 230 is configured to facilitate placement of region 230 at the aortic valve. For some applications, tube 24 includes the narrow region 230 even without the pitot tube 225 to facilitate placement of this region of the tube at the aortic valve in the manner described above.

[0367] Now refer to Figure 18This is a schematic diagram of a ventricular assist device 20 according to some applications of the invention, which includes coronary artery tubing and / or wires 304. For some applications, one or more tubing and / or wires extend externally or internally along a proximal portion of tubing 24. The tubing and / or wires are shaped such that, in a non-radially constrained configuration, the distal ends of the tubing and / or wires extend radially from the outer surface of tubing 24. The tubing and / or wires are positioned to extend radially along tubing 24 from an axial position such that, when the distal ends of the tubing and / or wires are positioned at the coronary artery 306 of the subject, the pump portion 27 of the device is correctly positioned within the left ventricle 22 of the subject. For some applications, the medical personnel deploying the ventricular assist device 20 ensure that the pump portion 27 of the device is correctly positioned within the left ventricle 22 of the subject by inserting the distal ends of the tubing and / or wires into the coronary artery 306. For some applications, a tube is used in the above embodiments, and the tube extends proximally to the proximal end of the ventricular assist device (e.g., via external tubes 140, 142 and / or via delivery catheter 143). In some such applications, surgery is performed via the tube on one or more coronary arteries. Alternatively or additionally, contrast agent is injected via the tube to aid in imaging the current position of the device. For some applications, a substantially similar technique is performed using the ventricular blood pressure measurement tube 220 as described above. For example, contrast agent can be injected via the blood pressure measurement tube to aid in imaging the current position of the device.

[0368] Now refer to Figure 19A , Figure 19B , Figure 19C , Figure 19D , Figure 19E , Figure 19F , Figure 19G and Figure 19H These figures are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, the device including a liner 39 that lining the interior of a receiving impeller 50 within a frame 34. For illustrative purposes, in Figures 19A-19E In this design, the liner 39 and tube 24 on the side of the device facing outwards from the paper are shown as transparent. For some applications, the liner 39 is disposed within the frame 34 to provide a smooth inner surface over which blood pumped by the impeller passes. Typically, by providing a smooth surface, the covering material reduces hemolysis caused by blood pumped by the impeller compared to blood being pumped between the impeller and the supports of the frame 34. For some applications, the liner comprises polyurethane, polyester, and / or silicone. Alternatively or additionally, the liner comprises polyethylene terephthalate (PET) and / or polyether block amide.

[0369] Typically, the lining is disposed on at least the inner surface of the columnar portion of the frame 34 (e.g., the columnar portion on...). Figures 2A-2C(As shown in the diagram). For some applications, tube 24 also covers the cylindrical portion 38 of frame 34, for example, around the outside of the frame, such that tube 24 and liner 39 overlap for at least 50% of the liner length, for example, over the entire length of the cylindrical portion of frame 34, such as... Figure 19A As shown. For some applications, there is only partial overlap between tube 24 and liner 39, for example, as Figure 19B As shown. For example, the tube 24 may overlap the liner along less than 50% (e.g., less than 25%) of the liner length. In some such applications, during insertion of the ventricular assist device 20 into the subject, the impeller is advanced distally within the frame 34 such that the impeller is not positioned in the overlapping area between the tube and the liner, thus eliminating a longitudinal position where the impeller, tube 24, frame 34, and liner 39 all overlap each other.

[0370] Typically, for example Figure 19A and Figure 19B In the application shown, in the overlapping area between the liner 39 and the tube 24, the liner is shaped to form a smooth surface (e.g., to reduce hemolysis, as described above), and the tube 24 is shaped to conform to the supports of the frame 34 (e.g., as shown above). Figure 19A (as shown in the cross-section). Typically, in the overlapping area between the liner 39 and the tube 24, the tube and the liner are joined together, for example, via vacuum, via adhesive and / or using thermoforming processes, as described below.

[0371] For some applications, the liner 39 and the tube 24 are made of different materials. For example, the liner may be made of polyurethane, while the tube may be made of polyether block amide. Manufactured. Typically, the material used to manufacture the liner has a higher thermoforming temperature than the material used to manufacture the tube. For some applications where the liner and tube overlap along at least a portion of the frame 34 (e.g., along the columnar portion of the frame 34), the tube and liner are bonded to each other and / or bonded to the frame in the following manner: Initially, the liner is placed on a mandrel. Subsequently, the frame is placed on the liner. Next, the tube 24 is placed around the outside of the frame. For some applications, in order to mold the tube 24 to conform to the supports of the frame 34 without causing deformation of the liner, the frame is heated to a temperature higher than the thermoforming temperature of the tube 24 but lower than the thermoforming temperature of the liner 39. Typically, the frame is heated from the inside using a mandrel. Typically, when the frame is heated to the aforementioned temperature, the outer tube (which is typically made of silicone) applies pressure to the tube 24, causing the tube 24 to be pushed radially inward so that the tube conforms to the shape of the supports of the frame, such as... Figure 19A The cross-section is shown. For some applications, the combination of the frame, liner, and portions of tube 24 arranged around the frame is then shaped to the desired shape and size using shaping techniques known in the art.

[0372] Based on the above description, the scope of the present invention includes a method of manufacturing a housing for an impeller of a blood pump, the method comprising performing the following steps: placing a liner around a mandrel; placing a cylindrical portion of a frame around the liner, the cylindrical portion of the frame including struts defining a generally cylindrical shape; placing a distal portion of an elongated tube around at least a portion of the frame, the tube including a proximal portion defining at least one blood outlet opening; while the distal portion is disposed around at least a portion of the frame, the liner, frame, and distal portion of the elongated tube are heated via the mandrel; while the liner, frame, and distal portion of the elongated tube are heated, pressure is applied from outside the distal portion of the elongated tube to conform the distal portion of the elongated tube to the strut structure of the frame and to make the liner and distal portion of the elongated tube connected to the frame. For example, pressure can be applied by a silicone tube placed outside the distal portion of the elongated tube. For some applications, the liner and the elongated tube comprise liner and elongated tube made of different materials from each other, and the thermoforming temperature of the material manufacturing the liner is higher than the thermoforming temperature of the material manufacturing the elongated tube. For some such applications, the liner, frame, and distal portion of the elongated tube are heated to temperatures higher than the thermoforming temperature of the material used to manufacture the elongated tube and lower than the thermoforming temperature of the material used to manufacture the liner.

[0373] Reference Figure 19C For some applications, tube 24 does not overlap with liner 39, but tab 322 extends from tube 24 through the strut of frame 34 to liner 39 and is used to sealably attach tube to liner (e.g., by adhesion to liner). Alternatively or additionally (not shown), tab 322 extends from liner to tube 24 and is used to sealably attach tube to internal material (e.g., by adhesion to tube).

[0374] As described above, for some applications, shaping techniques known in the art are used to shape the combination of the frame, liner, and portions of the tube 24 surrounding the frame into the desired shape and size. (Refer to...) Figure 19DFor some applications, the combination of the frame, liner, and portions of the tube 24 surrounding the frame is configured such that the distal portion 330 of the cylindrical portion 38 of the frame is wider relative to the rest of the cylindrical portion of the frame. Typically, the widening of the frame causes the blood inlet opening 108 (typically defined by the liner at the distal end of the cylindrical portion of the frame) to be wider relative to the rest of the cylindrical portion of the frame. Typically, throughout the entire operation of the impeller (and during axial reciprocating motion), the impeller is positioned very close to the blood inlet opening, wherein the distal end of the impeller is typically positioned within 15 mm of the blood inlet opening throughout the entire operation of the impeller. For some applications, having a widened blood inlet opening very close to the impeller reduces turbulence generated as blood flows into the blood inlet opening. Compared to a frame-defined, non-widened blood inlet opening, the reduction in turbulence typically increases blood flow and / or reduces hemolysis caused by the impeller.

[0375] Reference Figure 19E For some applications, the combination of the frame, liner, and portions of the tube 24 surrounding the frame is shaped such that the distal portion 332 of the cylindrical portion 38 of the frame converges from the distal end of the cylindrical portion of the frame toward the impeller (e.g., defining a frame portion narrower than the rest of the cylindrical portion of the frame near the impeller (e.g., near the distal end of the impeller)). For some applications, converging a portion of the frame toward the impeller reduces turbulence generated as blood flows from the blood inlet opening toward the impeller. Compared to a frame without a converging portion, this reduction in turbulence typically increases blood flow and / or reduces hemolysis caused by the impeller.

[0376] Reference Figure 19F For some applications, the combination of the frame, liner, and the portion of tube 24 surrounding the frame is shaped such that, respectively, references... Figure 19D and Figure 19E The described features are combined. That is, the first distal portion 330 of the columnar section of the frame widens relative to the rest of the columnar section 38 of the frame, while the second portion 332 of the columnar section of the frame converges toward the impeller.

[0377] Reference Figure 19G For some applications, tube 24 does not extend to the distal end of the cylindrical portion 38 of frame 34. For some such applications, along the portion of the frame to which the tube extends, the tube is configured to limit the radial expansion of the frame. Along the distal portion of the cylindrical portion of the frame (on which the tube does not extend), the expansion of the frame is not limited by tube 24. Therefore, the distal portion of the cylindrical portion of the frame is wider than the proximal portion of the cylindrical portion of the frame to which tube 24 extends. For some applications, this causes the blood inlet opening 108 to be wider than when tube 24 extends along the entire length of the cylindrical portion of the frame. See reference... Figure 19DTypically, throughout the impeller's operation (and axial reciprocating motion), the impeller is positioned very close to the blood inlet opening, with the distal end of the impeller typically within 15 mm of the blood inlet opening. For some applications, a widened blood inlet opening very close to the impeller reduces turbulence as blood flows into the blood inlet opening. Compared to a frame-defined, non-widened blood inlet opening, this reduction in turbulence typically increases blood flow and / or reduces hemolysis caused by the impeller.

[0378] Reference Figure 19H For some applications, to facilitate the attachment of the liner 39 to the frame 34, the outer covering material is attached from the outer frame 34 to the liner at certain discrete attachment areas 326 along the frame length (e.g., using adhesives, vacuum and / or thermoforming processes). Note that in Figure 19H For illustrative purposes, only the catheter 24 and frame 34 are shown, without other components of the ventricular assist device (e.g., impeller and axial shaft). For some applications, in at least one of these connection areas, the tube 24 includes an external covering material, such as... Figure 19G The connection area on the right-hand side is shown. Alternatively or additionally, at one or more connection areas, additional external covering material 328 is placed around the frame 34. For example, the additional connection material may be made of a similar material to that used for the liner 39 and / or the tube 24. For some applications, at the connection areas, the frame 34 has a lower strut density (i.e., the ratio of the surface area occupied by the struts to the area of ​​the opening space between the struts) compared to the strut density of the frame at other locations along the frame length. For example, as... Figure 19G As shown, along the columnar portion 38 of the frame, at the connection area where the frame has straight axial struts 329 (conversely, in other areas within the columnar portion of the frame), the frame defines serrated struts, and proportionally, there are two serrated struts for each straight strut. Typically, the reduced strut density at the connection area allows the outer covering material to be directly bonded to the liner over a larger surface area compared to the frame not having a reduced strut density at the connection area.

[0379] Now refer to Figure 20A , Figure 20B and Figure 20C These figures are schematic diagrams of a ventricular assist device 20 according to some applications of the present invention, the ventricular assist device 20 including an inflatable portion 331 (e.g., a balloon), the inflatable portion in Figure 20A , Figure 20B and Figure 20C Each of them is in a corresponding expanded state. For some applications (as shown), the expandable portion 331 is in accordance with the above reference. Figure 13DThe expandable portion 153 shown expands in a substantially similar manner to that described above. That is, the expandable portion expands by a cleaning fluid entering the interior of the expandable portion via the opening 155. For some applications, the expansion of the expandable portion is controlled by controlling the pressure at which the cleaning fluid is pumped into the ventricular assist device 20. Alternatively or additionally, the expansion lumen for expanding the expandable portion is configured to pass through the outer tube 142 and subsequently along the outer surface of the tube 24, reaching the distal tip portion of the expandable portion.

[0380] For some applications, the expandable portion is configured to be in a corresponding expanded state during various stages of ventricular assist device deployment. For some applications, the distal tip portion 120 has a radially converging shape (e.g., Figures 20A-20C As shown), and configured to act as a dilator during insertion of a ventricular assist device via a puncture in the subject's body, as described above. In this way, the delivery catheter 143 and the components of the ventricular assist device disposed within the delivery catheter can be inserted into the puncture without pre-dilation of the puncture, and without the need for a separate guiding device to facilitate insertion of the delivery catheter through the puncture. Typically, during insertion of the distal tip portion via a puncture in the subject's body, the expandable portion 331 remains in a constricted state, as... Figure 20A As shown.

[0381] In some applications, after the distal tip is inserted via a puncture in the subject's body, it is used to guide the delivery catheter along curved anatomical structures (such as the aortic arch). In some applications, at this stage of the procedure, the expandable portion is partially inflated to prevent damage to the subject's vascular system from the distal tip. The expandable portion in... Figure 20B The figure shows a partially expanded state.

[0382] For some applications, where the ventricular assist device 20 is deployed such that the distal tip portion is in the left ventricle of the subject, the inflatable portion 331 is more inflatable than the inflatable portion. Figure 20B The state shown is a more complete expansion (e.g., full expansion). Typically, when the expandable portion expands more completely, it separates one or more blood inlet openings 108 from the three-dimensional internal structures of the left ventricle. In this way, the expandable portion separates one or more blood inlet openings 108 from the intraventricular septum, chordae tendineae, papillary muscles, and / or the apex of the left ventricle. For some applications, the expandable portion is shaped to guide blood from the left ventricle into one or more blood inlet openings.

[0383] Typically, a hemostatic valve (e.g., a duckbill valve 390) is disposed within the lumen 122 of the distal tip portion 120. For some applications, the hemostatic valve prevents blood from flowing into the lumen 122 and / or the lumen 132. Typically, the hemostatic valve prevents the flow of cleaning fluid out of the distal end of the lumen 122, thus directing the cleaning fluid toward the interface between the axial shaft 92 and the distal support 118, as described above.

[0384] Now refer to Figure 21 This is a schematic diagram (showing a cross-sectional view of the left ventricle) of a ventricular assist device 20 placed within the left ventricle 22 of a subject, according to some applications of the present invention. For illustrative purposes, Figure 21 The aortic valve 26 is shown covering a cross-section of the left ventricle, although the aortic valve lies in a different plane than the plane of the main sectional view. See also... Figures 22A-22D These figures are schematic diagrams of the distal tip element 107 of a ventricular assist device according to some applications of the invention, which is at least partially curved to define a curvature resembling a question mark, and also refer to... Figure 23A and Figure 23B These figures are arrangements placed in the left ventricle of a subject according to some applications of the present invention. Figures 22C-22D A schematic diagram of a ventricular assist device.

[0385] In some applications, the ventricular assist device is guided by a guide wire, through which it is inserted toward the apex 342 of the left ventricle. The wall of the left ventricle can be considered to consist of a septal wall 338 (which separates the left ventricle from the right ventricle 340), a posterior wall 336 (from which papillary muscles 341 protrude, and mitral valve devices are positioned above the posterior wall 336), and a free wall 334, each of which occupies approximately one-third of the circumference of the left ventricle (e.g., ...). Figure 21 (The dashed lines dividing the left ventricle into three equal parts are shown). Typically, it is undesirable for the distal tip element (or any other part of the ventricular assist device) to contact the diaphragmatic wall, as this could potentially lead to arrhythmias. More typically, it is desirable to maintain a distance between the distal tip element (and any other part of the ventricular assist device) and the posterior wall so as not to interfere with the mitral valve device and to prevent the mitral valve device from interfering with the function of the ventricular assist device. Therefore, the ventricular assist device is typically guided toward the apex in such a way that if and when the distal tip element contacts the ventricular wall of the left ventricle, the ventricular assist device contacts the free wall 334, as shown. Figure 21 and Figures 23A-23B As shown.

[0386] Typically, as described above, the ventricular assist device is introduced into the ventricle of a subject via a guideline. The distal tip portion 120 defines a guideline lumen 122 such that the distal tip portion remains in a straight configuration during introduction of the ventricular assist device into the subject's ventricle. For some applications, the distal tip portion is configured to exhibit its curved shape when the guideline is removed. Note that... Figures 22A-22D The shape of the distal tip portion 120 initially formed is shown. Typically, due to the insertion of the guide wire through the guide wire lumen 122 (thus temporarily straightening the distal tip portion), the curvature of the distal tip portion is less than that of the guide wire when deployed in the left ventricle of the subject. Figures 22A-22D The curvature shown in at least some of the diagrams. For example, Figures 22C-22D The curvature of the distal tip portion is shown to cause the curved portion of the distal tip portion to form a complete loop. However, Figures 22C-22D The distal tip portion in Figure 23A The image shows the left ventricle of the subject, and the distal tip portion does not form a complete ring.

[0387] As described above, the distal tip portion 120 typically forms part of the distal tip element 107, which also includes an axial shaft receiving tube 126. Typically, the distal tip element 107 is configured such that in its unconstrained configuration (i.e., without any force acting on the distal tip portion), the distal tip element is at least partially bent. For some applications, in a given plane, the distal tip element 107 has a proximal straight portion 346 (at least a portion of which typically includes the axial shaft receiving tube 126). The proximal straight portion of the distal tip element 107 defines a longitudinal axis 348. The bent portion of the distal tip element 107 bends away from the longitudinal axis 348 in a first direction and then, at an inflection point, bends relative to the longitudinal axis 348 in the opposite direction. For example, as... Figures 22A-22B As shown, within the plane of the paper, the distal tip element first bends towards the top of the paper, then towards the bottom, and as... Figures 22C-22D As shown, within the plane of the paper, the distal tip element first bends towards the bottom of the paper and then towards the top. Typically, when shaped as... Figures 22A-22D As shown, the distal tip element defines an overall curvature resembling a question mark or a tennis racket, and the distal tip element defines a ridge 351 on one side of the longitudinal axis of the flat proximal portion of the distal tip element. For some applications, the ridge is generally shaped as a semi-ellipse. Note that in this context, the term "semi-ellipse" includes a semicircle. It should also be noted that in some cases, the tip does not define a precise semi-ellipse, but rather a ridge shape that is substantially similar to a semi-ellipse.

[0388] like Figures 22A-22BAs shown, for some applications, after the inflection point, the distal tip element continues to bend, causing the distal tip element to cross back onto the longitudinal axis 348. Figure 22A An example is shown in which the end of the distal tip element has not yet crossed back onto the longitudinal axis, and there is a large gap between the distal end of the distal tip element and the proximal end of the curved portion. Figure 22B An example is shown where the end of the distal tip element crosses back onto the longitudinal axis again, and a small gap exists between the distal end of the distal tip element and the proximal end of the curved portion. (See example...) Figures 22C-22D As shown (these figures are cross-sectional and isometric views of the distal tip element of the same shape, respectively), for some applications, after the inflection point, the tip does not bend such that the distal tip element crosses back onto the longitudinal axis 348. Instead, all the curvature of the bent portion of the distal tip element appears on one side of the longitudinal axis 348.

[0389] Reference Figure 22A and Figure 22C Typically, a hemostatic valve (e.g., a duckbill valve 390) is located within the distal segment of the distal tip portion 120 and is configured to prevent blood from flowing into the lumen 122. For some applications, the duckbill valve 390 is described below. Figures 28A-28C To describe in further detail. For example, Figure 22A It shows the use of Figures 28A-28C An example of a duckbill valve. Alternatively, different duckbill valves can be used, such as... Figure 22C As shown. Typically, the maximum width of the duckbill valve is less than 3 mm, for example, less than 2 mm. Typically, the entire duckbill valve is located within the distal segment of the distal tip portion, which is located within the farthest 10 mm of the distal tip portion, for example, within the farthest 5 mm of the distal tip portion. For some applications, the duckbill valve faces proximal (i.e., the wide inlet of the valve faces the distal end of the distal tip portion, and the narrow tip of the valve faces away from the distal end of the distal tip portion 120), as shown below. Figures 28A-28E Further detailed description. For some applications, the guide wire guide 392 is positioned within the distal tip portion 120 proximal to the duckbill valve (e.g., as...). Figure 22A As shown). Figures 22A-22D As shown, typically, the distal segment of the distal portion is widened to accommodate the duckbill valve and / or guide wire guide. For some applications, due to the widening of the distal portion, the distal tip of the distal tip portion (through which the guide wire is inserted) lacks a sharp edge. More precisely, the edge has a width greater than 1 mm. Typically, the absence of a sharp edge at the distal tip of the distal tip portion helps prevent damage to structures within the left ventricle from the distal tip of the distal tip portion.

[0390] Typically, when deployed in the left ventricle of a subject, the curvature of the curved portion of the distal tip element 107 is configured to provide a trauma-resistant tip to the ventricular assist device 20. More typically, the distal tip element is configured to separate the inlet opening 108 of the ventricular assist device from the wall of the left ventricle.

[0391] Now refer to Figure 23A and Figure 23B First, note that these figures show a cross-sectional view of the left ventricle 22, with the septal wall 338 positioned on the left side of the page and the free wall 334 on the right side. In this view, the left atrium 359 and left atrial appendage 358 are visible above the left ventricle, and the right ventricle 340 is visible to the left of the left ventricle. For some applications, the distal tip element 107 is configured to separate the blood inlet opening from the posterior wall of the subject's left ventricle when the distal tip element is placed against the apex of the subject's left ventricle. Typically, the distal tip element is configured to separate the blood inlet opening from the septal wall of the subject's left ventricle when the distal tip element contacts the apex of the subject's left ventricle.

[0392] Typically, the distal tip element 107 is inserted into the left ventricle such that the bulge 351 bulges toward the diaphragm wall 338. When configured in this way, in response to the distal tip element 107 being pushed to its apex (e.g., due to a physician's advance mechanism or in response to movement of the left ventricle), the blood inlet opening is typically pushed toward the free wall 334 and away from the diaphragm wall 338 (in Figure 23B (In the direction of the arrow shown). Typically, this is due to the proximal straight portion 346 pivoting around the question mark-shaped curved portion, as shown. In contrast, other shaped tips, if set in a similar orientation, may cause the blood inlet opening to be pushed toward the septum wall. For example, if the distal tip element has a pigtail tip (where the tip bends along a single curvature direction) oriented such that the pigtail bend is on the free wall side of the longitudinal axis of the straight portion of the distal tip element, then pushing the tip distally will typically cause the blood inlet opening toward the septum wall due to the tightening of the pigtail bend ring.

[0393] Now refer to Figure 24A , Figure 24B , Figure 24C These figures are schematic diagrams of a distal tip element 107 according to some applications of the invention, the distal tip element being configured to center itself relative to the aortic valve 26. Figure 24A As shown, for some applications, the curved distal portion is shaped such that, after bending in the first direction and before bending in the second direction, the curved distal portion defines an elongated straight portion 353. For example... Figure 24BAs shown, the distal tip element is configured such that, when released within the subject's aorta, the distal tip element itself is centered relative to the aortic valve 26. Therefore, the distal tip portion can be used to guide the ventricular assist device through the aortic valve in a trauma-free manner. This may be desirable, for example, in the event that the ventricular assist device is mistakenly retracted from the left ventricle through the aortic valve after the distal tip element has been released within the left ventricle. (See reference...) Figure 24C An alternative or additional way to provide the aforementioned function by configuring the distal tip element is that the radius of the bulge 351 of the distal tip element is large enough to center the distal tip element relative to the aortic valve. For example, the radius of the bulge of the distal tip element may be greater than 15 mm (e.g., greater than 17 mm).

[0394] Reference Figures 21-24C All figures in the invention include the use of a question mark or tennis racket-shaped distal tip element in combination with any ventricular assist device, even without other features and / or portions of the distal tip element 107 (e.g., axial shaft receiving tube 126).

[0395] Now refer to Figure 25A This is a schematic diagram of a ventricular assist device 20 according to some applications of the invention, wherein the tube 24 of the device is configured to bend as blood is pumped through the tube. Also see... Figure 25B This is according to some applications of the invention in the absence of other components of a ventricular assist device. Figure 25A A schematic diagram of tube 24. Also refer to... Figure 25C It is disposed within the aorta 30 and left ventricle 22 of the subject according to some applications of the present invention. Figures 25A-25B A schematic diagram of the ventricular assist device 20. Note that, as shown... Figure 25C The views of the aorta and left ventricle shown are different from, for example... Figure 1B The view shown. Figure 1B Similar diagrams are illustrative and provided for purposes of explanation, and do not necessarily depict the precise proportions and orientation of ventricular assist devices relative to anatomical structures. Also note that, as... Figure 25C The views of the aorta and left ventricle shown are different from, for example... Figure 23A and Figure 23B The view shown. Figure 25C A cross-sectional view of the left ventricle is shown, with the posterior wall 336 positioned on the left side of the page and the free wall 334 positioned on the right side of the page.

[0396] As described above, for some applications, the frame 34 is not disposed within the tube along the proximal portion of the tube 24, so the tube is not supported by the frame 34 in the open state. The tube 24 is typically made of a collapsible material that is impermeable to blood. For example, the tube 24 may comprise polyurethane, polyester, and / or silicone. Alternatively or additionally, the tube may be made of polyethylene terephthalate (PET) and / or polyether block amide. The tube is manufactured. Typically, the proximal portion of the tube is configured to be positioned such that it is at least partially located within the subject's ascending aorta. For some applications, the proximal portion of the tube passes through the subject's aortic valve, entering the subject's ascending aorta from the subject's left ventricle, such as... Figure 1B As shown. As described above, the tube typically defines one or more blood inlet openings 108 at its distal end, through which blood flows from the left ventricle into the tube during impeller operation. For some applications, the proximal portion of the tube defines one or more blood outlet openings 109, through which blood flows from the tube into the ascending aorta during impeller operation. During impeller operation, the blood flow pressure through the tube typically keeps the proximal portion of the tube open.

[0397] For some applications, tube 24 is pre-formed such that, during impeller operation, the tube is curved when the blood flow pressure through it keeps the proximal portion of the tube open. Typically, the curvature is such that, when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the posterior wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. Furthermore, typically, the curvature is such that, when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the diaphragmatic wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. For some applications, the curvature of the tube maintains separation between the blood inlet opening 108 and the posterior wall 336 of the left ventricle, the mitral valve leaflet 402, and / or the subvalvular portion of the mitral valve (e.g., chordae tendineae 404 and / or papillary muscles 341), such as... Figure 25C As shown.

[0398] Typically, tube 24 is pre-formed using a blow molding die in a bending mold, or pre-formed using a molding die after a blow molding or dip molding process. Typically, the distal portion of the tube (where the frame 34, impeller 50, and axial shaft 92 are disposed) is held in a straight and open configuration by the frame 34. The portion of the tube located proximal to the frame 34 and within the left ventricle is typically shaped to define the aforementioned curvature. For some applications, the curvature is such that the angle gamma between the longitudinal axis of the tube at its proximal end and the longitudinal axis of the tube at its distal end is greater than 90 degrees (e.g., greater than 120 degrees, or greater than 140 degrees), and / or less than 180 degrees (e.g., less than 160 degrees, or less than 150 degrees), for example, 90-180 degrees, 90-160 degrees, 120-160 degrees, or 140-150 degrees. For some applications, the curvature of the tube is such that the surface of the tube located inside the bend defines a radius of curvature R, which is greater than 10 mm, for example greater than 20 mm, and / or less than 200 mm (e.g. 100 mm), for example 10 mm-200 mm, or 20 mm-100 mm. Figure 25B The diagram shows a dashed circle, with the dashed line spanning its diameter, to indicate how the radius of curvature R is measured.

[0399] Note that, as referenced Figures 25A-25C The tube 24 is configured such that (a) in the absence of blood flow through the tube, the tube typically collapses in response to external pressure exceeding internal pressure, and (b) when blood flows through the tube at a sufficient rate, causing internal pressure to exceed external pressure, the tube assumes its pre-formed bent configuration. It should also be noted that when the tube 24 assumes its bent configuration, the tube typically causes the portion of the drive cable 130 disposed within the bent portion of the tube to also bend, such as... Figure 25A and Figure 25C As shown. That is, it is the preforming of the tube itself that typically causes the tube and drive cable to bend, rather than the drive cable (or different components disposed within the tube) causing the tube to bend. Alternatively, the outer tubes 140 and / or 142 (which are disposed around the drive cable) are shaped to define a curve, and the outer tubes cause the drive cable and tube 24 to take on a bent shape. For some applications, both the outer tubes 140 and / or 142 and tube 24 are shaped to define a bent shape.

[0400] Note that, as Figures 25A-25C The tube 24 shown is roughly as described above. Figure 2A The configuration is described above (i.e., having a tapered distal portion 46 and a plurality of blood inlet openings 108). However, the scope of the invention includes reference to... Figures 25A-25C The described curved configuration of the tube is combined with other general tube configurations (e.g., as described above).

[0401] Now refer to Figures 25D-25EThese figures are schematic diagrams of a ventricular assist device 20 according to some applications of the invention, wherein the tube 24 of the device is configured to bend as blood is pumped through the tube. Figure 25D and Figure 25E In the illustration, tube 24 is shown without other components of the ventricular assist device (e.g., impeller 50, frame 34, etc.). Figure 25E According to some applications of the present invention, the aorta 30 and left ventricle 22 of the subject are disposed therein. Figure 25D A schematic diagram of the ventricular assist device 20. Figure 25E The view of the left ventricle shown is similar to Figure 25C The view shown. For some applications, the inlet opening 108 and / or outlet opening 109 are configured in a non-axisymmetric configuration around the tube 24. Typically, the tube 24 defines the positions of the inlet opening and / or outlet opening such that the tube 24 becomes curved and / or maintains the curvature of the tube 24, as shown in the reference. Figures 25A-25C As shown, for example, a blood inlet orifice may be located on one side of tube 24 located inside the bend of the tube (or on the inside of the desired bend of the tube). As blood flows into the blood inlet orifice, this reduces the pressure in the region above the blood inlet orifice, and the distal end of tube 24 is pulled toward that region (as indicated by arrow 310). Alternatively or additionally, a blood outlet orifice 109 may be located on one side of tube 24 located inside the bend of the tube (or on the inside of the desired bend of the tube). As blood flows out of the blood outlet orifice, the blood impacts the aortic wall, causing the proximal end of tube 24 to be pushed in the opposite direction, i.e., in the direction of arrow 312.

[0402] For reference Figures 25A-25C Typically, the curvature of the tube maintains separation between the blood inlet opening 108 and the posterior wall 336 of the left ventricle, the mitral valve leaflet 402, and / or the subvalvular portion of the mitral valve (e.g., chordae tendineae 404 and / or papillary muscles 341), as... Figure 25E As shown. Typically, the curvature is such that when the proximal end of the tube is placed within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the posterior wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. More typically, the curvature is such that when the proximal end of the tube is placed within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the septal wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall.

[0403] Now refer to Figure 25F This is a schematic diagram of a ventricular assist device 20 according to some applications of the present invention, which includes a bending element 410 configured to provide a predetermined curvature to a tube 24. For some applications, the tube 24 itself is shaped to define a bend (e.g., as shown in reference...). Figures 25A-25E As an alternative or supplement to the aforementioned, the ventricular assist device includes a bending element 410. Typically, the bending element is made of a shape memory material, such as a nitinol shape memory alloy. For some applications, the bending element is formed from a nitinol tube that is cut to define holes or slots, allowing the tube to be pre-shaped into the desired bending shape. For example, the nitinol element may be a nitinol “hypo tube” (i.e., a nitinol tube with micro-engineered features along its length) known in the art. Typically, the bending element 410 is positioned around the drive cable 130 along a longitudinal segment of the drive cable proximal to (e.g., directly proximal to) the proximal radial support 116. For some applications, the bending element is used in place of the outer tube 142 along this longitudinal segment of the drive cable.

[0404] For some applications, the bending element is shaped to be roughly similar to the reference. Figures 25A-25E Regarding the curvature described for tube 24. For some applications, the curvature causes the angle between the longitudinal axis of the bending element at its proximal end and the longitudinal axis of the bending element at its distal end to be greater than 90 degrees (e.g., greater than 120 degrees, or greater than 140 degrees) and / or less than 180 degrees (e.g., less than 160 degrees, or less than 150 degrees), such as 90-180 degrees, 90-160 degrees, 120-160 degrees, or 140-150 degrees. For some applications, the curvature of the tube is such that the radius of curvature defined by the surface of the bending element located inside the bend is greater than 10 mm, such as greater than 20 mm, and / or less than 200 mm (e.g., 100 mm), such as 10 mm-200 mm, or 20 mm-100 mm. See reference. Figures 25A-25C As stated, typically, such as Figure 25C As shown, the curvature of the tube maintains separation between the blood inlet opening 108 and the posterior wall 336 of the left ventricle, the mitral valve leaflet 402, and / or the subvalvular portion of the mitral valve (e.g., chordae tendineae 404 and / or papillary muscles 341). Typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the posterior wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall. Furthermore, more typically, the curvature is such that when the proximal end of the tube is positioned within the aorta, at least a portion of the tube is positioned within the left ventricle and bends away from the septal wall of the left ventricle, toward the apex of the left ventricle, and / or toward the free wall.

[0405] Reference Figures 25A-25F Note that for some applications, because the outer tube 142 is anchored to the aorta and the distal tip portion 120 becomes anchored to the left ventricular wall (e.g., the free wall near the apex), the tube 24 adopts a curved shape, as described above. It should also be noted that... Figures 23A-23B The curvature of the tube shown is less than Figures 25A-25F The curvature of the tube shown is because Figures 23A-23B Different views of the device are shown. Figures 23A-23B In the view shown, the curvature is typically less than Figures 25A-25F The view shown is clear.

[0406] Now refer to Figure 26A , Figure 26B , Figure 26C , Figure 26D , Figure 26E and Figure 26F These figures are schematic diagrams of the distal tip element 107 of a ventricular assist device 20 according to a corresponding application of the invention, which is at least partially curved. Figures 26B-26F The distal tip element 107 is shown without the distal end of frame 34. Typically, as described above, the ventricular assist device is introduced into the ventricle of a subject via a guideline. The distal tip portion 120 defines a guideline lumen 122 such that the distal tip portion maintains a flat configuration during introduction of the ventricular assist device into the subject's ventricle. For some applications, the distal tip portion is configured to present as shown when the guideline is removed. Figures 26A-26F One of the shapes shown.

[0407] Typically, the distal tip element 107 is configured such that in its unconstrained configuration (i.e., without any force acting on the distal tip portion), the distal tip element is at least partially bent. For some applications, the distal tip element bends about an angle greater than 90 degrees (e.g., greater than 120 degrees) and less than 180 degrees (e.g., less than 160 degrees), such as 90 degrees–180 degrees, 120 degrees–180 degrees, or 120 degrees–160 degrees, for example, as... Figure 26A As shown.

[0408] For some applications, the distal tip element defines a first proximal bend 343 and a second distal bend 344, such as... Figure 26B As shown. For some applications, the first bend defines an angle theta (θ) greater than 130 degrees (e.g., greater than 140 degrees) and / or less than 160 degrees (e.g., less than 150 degrees), such as 130-160 degrees or 140-150 degrees. For some applications, the second bend defines an angle alpha (α) greater than 110 degrees (e.g., greater than 120 degrees) and / or less than 140 degrees (e.g., less than 130 degrees), such as 110-140 degrees or 120-130 degrees. Typically, the stiffness of the bends 343, 344 of the distal tip element 107 is less than the stiffness of the proximal straight portion 346 of the distal tip element, which is disposed between the two bends. For some applications, the stiffness of the second bend 344 is less than the stiffness of the first proximal bend 343.

[0409] Reference Figure 26C and Figure 26D For some applications, within a given plane, the distal tip element has a proximal straight portion 346 defining a longitudinal axis 348, curved away from the longitudinal axis 348 in a first direction, and subsequently curved relative to the longitudinal axis 348 in the opposite direction. For example, as Figure 26C As shown, within the plane of the page, the distal tip element first bends to the left of the page, then to the right, and subsequently bends to the left again. Or, as... Figure 26D As shown, within the plane of the page, the distal tip element first bends to the right of the page, and then bends to the left of the page. Figure 26D The example shown is roughly similar to Figure 22A The example shown, except in Figure 26D The tip is configured such that the portion distal to the intersection of the tip and the longitudinal axis 348 is larger than... Figure 22A (The short one in the middle).

[0410] Note that when... Figure 26C As shown in the forming process, the distal tip element 107 typically defines a first turning point 347 and a second turning point 349. The first turning point 347 is located on a first side (e.g., to the left of the longitudinal axis 348) of the proximal straight portion 346 of the distal tip portion 120. Figure 26C As shown), the second turning point 349 is located on the opposite side of the longitudinal axis 348 of the proximal straight portion 346 of the distal tip portion 120 (e.g., to the right of the longitudinal axis, as shown). Figure 26C (As shown). For some applications, the distal tip portion is thus shaped to define two ridges on either side of the longitudinal axis 348. Typically, as shown, the distal ridge 412 is larger (e.g., wider) than the proximal ridge 411. For some applications, the ridges are generally shaped as semi-ellipses. Typically, as shown, the distal semi-ellipse defines a larger radius than the proximal semi-ellipse. Note that in this context, the term "semi-ellipse" includes a semicircle. It should also be noted that in some cases, the tip does not define two precise semi-ellipses, but rather a ridge shape that is substantially similar to a semi-ellipse.

[0411] Typically, when Figure 26D As shown in the forming process, the distal tip element defines an overall curvature resembling a question mark, and the tip portion defines a ridge 351 on one side of the longitudinal axis of the straight proximal portion of the distal tip portion. For some applications, the ridge is generally formed as a semi-ellipse. It should be noted that, in this context, the term "semi-ellipse" includes a semicircle. It should also be noted that in some cases, the tip is not defined as a precise semi-ellipse, but rather as a ridge that is substantially similar to a semi-ellipse.

[0412] Typically, when deployed in the left ventricle of a subject, the curvature of multiple portions of the distal tip element 107 is configured such that the tip portion 120 provides trauma resistance. More typically, the distal tip portion is configured to separate the inlet opening 108 of the ventricular assist device from the wall of the left ventricle.

[0413] For some applications, turning points are defined by bending in at least three directions, for example, on both sides of the longitudinal axis 348 (e.g., as...). Figure 26C As shown), and / or by bending in at least two directions (e.g., as shown) Figure 26D As shown, the distal tip element is configured to absorb the force exerted on the distal tip portion by the wall of the left ventricle, and this absorption is greater than if the distal tip element were bent in a single direction.

[0414] For some applications, the distal tip element 107 defines multiple bends, each bend defining a different radius of curvature, and / or the bends are in a corresponding direction, such as... Figure 26E and Figure 26F As shown.

[0415] As described above, for some applications, the duckbill valve 390 is disposed within the distal segment of the distal tip portion 120. The duckbill valve is described below. Figures 28A-28C Further details are shown and described.

[0416] Note that for all curved distal tip elements described herein (e.g., refer to...), Figures 21-24C and Figures 26A-26F Typically, the curvature of the distal tip portion lies within a single plane. Referring to the shape of the distal tip portion described herein (e.g., referring to...), Figures 21-24C The scope of the invention includes the use of a question mark or tennis racket-shaped distal tip portion in combination with any ventricular assist device, even without other features and / or portions of the distal tip element 107 (e.g., axial shaft receiving tube 126).

[0417] Now refer to Figure 27A , Figure 27B and Figure 27C These figures are schematic diagrams of anti-trauma protrusions 350 according to a corresponding application of the invention, which are configured to extend distally from the distal tip element 107 of the ventricular assist device 20. Figures 27A-27CThe protrusion 350 is shown without the distal tip element 107. For some applications, the trauma-resistant protrusion includes a closed ellipse or a closed circle. Typically, as described above, the ventricular assist device is introduced into the ventricle of a subject via a guideline. Along the proximal portion of the trauma-resistant protrusion 350, the trauma-resistant protrusion defines a guideline lumen 352. The closed circle or ellipse of the trauma-resistant protrusion typically defines holes 354 on its sidewalls, and the guideline passes through these holes. During insertion of the ventricular assist device into the subject's ventricle, the circle or ellipse is typically axially elongated by retaining the proximal portion of the circle or ellipse within the delivery catheter. More typically, the distal portion of the axially elongated circle or ellipse protrudes from the distal tip of the delivery catheter and serves as a trauma-resistant tip of the delivery catheter as the catheter passes through the subject's vascular system.

[0418] Typically, when deployed in the left ventricle of a subject, the protrusion 350 is configured to provide a trauma-resistant tip to the distal tip element 107. More typically, the protrusion is configured to separate the inlet opening 108 of the ventricular assist device from the wall of the left ventricle.

[0419] Figure 27A , Figure 27B and Figure 27C The corresponding shape of the protrusion 350 when it is in a non-radial constraint configuration is shown. Typically, the protrusion 350 is configured to present these shapes when it is deployed in the left ventricle of a subject.

[0420] Now refer to Figure 28A This is a schematic diagram of a duckbill valve 390 and a guide wire guide 392 according to some applications of the present invention, wherein the duckbill valve 390 and the guide wire guide 392 are disposed at the distal end of the distal tip portion 120 of the ventricular assist device. Also refer to... Figure 28B and Figure 28C These figures are schematic diagrams of the proximal narrow end 420 and the distal wide end 422 of a duckbill valve 390 according to some applications of the present invention. See also... Figure 28D and Figure 28E These figures are schematic diagrams of the proximal end 424 and the distal end 426 of the wire guide 392 according to some applications of the present invention.

[0421] It should be noted that although the duckbill valve 390 and guide wire guide 392 are shown at the distal end of a given example of the distal tip element 107, the scope of the invention includes combining the duckbill valve 390 and guide wire guide 392 with any other example of the distal tip element described herein. Furthermore, the scope of the invention includes the use of the duckbill valve 390 and guide wire guide 392 within the tip of any percutaneous device, and is not limited to their use within ventricular assist devices.

[0422] As described above, typically, the duckbill valve 390 has a maximum width of less than 3 mm, for example, less than 2 mm. Typically, the entire duckbill valve is positioned within the distal segment of the distal tip portion, which is located within the farthest 10 mm of the distal tip portion, for example, within the farthest 5 mm of the distal tip portion. More typically, as shown, the duckbill valve faces proximally (i.e., such that the wide inlet of the duckbill valve faces the distal end of the distal tip portion, and such that the narrow tip of the duckbill valve faces away from the distal end of the distal tip portion 120). This is because the pressure of the fluid typically pumped into the distal tip portion (e.g., as referred to above)... Figures 13A-13C The pressure in the left ventricle is greater than the blood pressure in the left ventricle. The duckbill valve faces proximally to prevent fluid from flowing out of the distal portion, allowing fluid to flow back toward the distal support 118, as described above. Typically, blood does not flow into the guideline lumen 122 because the pressure inside the guideline lumen 122 is greater than the blood pressure in the left ventricle outside that lumen.

[0423] Typically, ventricular assist devices are delivered via a guide wire (e.g., guide wire 10, such as...). Figure 1B (As shown) is advanced into the left ventricle. The guide wire is typically inserted into the guide wire lumen 122 of the distal tip portion 120 via the distal end of the distal tip portion. Typically, the insertion of the guide wire through the distal end of the distal tip portion is relatively straightforward because the distal wide end 422 of the duckbill valve 390 guides the guide wire through the duckbill valve.

[0424] In some applications, when a ventricular assist device (VAD) is placed in a subject, it may be desirable to insert another guideline from the proximal end of the VAD to the distal end of the distal tip portion. For example, if further surgery is to be performed on the subject's left ventricle after the VAD has been activated, it may be desirable to insert the guideline via the existing percutaneous puncture and through the guideline lumen 122 before retracting the VAD 20, rather than retracting the VAD and having to reinsert the guideline via percutaneous puncture.

[0425] Typically, to facilitate insertion of the lead wire through the lead wire lumen 122 from the proximal end of the ventricular assist device, the ventricular assist device includes a lead wire guide 392. The lead wire guide 392 is configured to facilitate insertion of the lead wire through the narrow proximal end 420 of a duckbill valve 390. The lead wire guide is shaped to define an aperture 432 therethrough, the diameter of which narrows from the proximal end 424 of the lead wire guide to the distal end 426 of the lead wire guide. The shape of the lead wire guide is configured to guide the tip of the lead wire toward a slit 434 at the narrow proximal end of the duckbill valve. For some applications, the duckbill valve is also shaped to define a converging guide portion 430 at its proximal end, the converging guide portion converging toward the slit 434, such that the guide portion is configured to further guide the tip of the lead wire toward the slit 434.

[0426] The scope of this invention includes the use of a duckbill valve 390 and a guide wire guide 392 within the lumen of any percutaneous device, and is not limited to their use within ventricular assist devices. Typically, the duckbill valve 390 and the guide wire guide 392 facilitate the insertion of the guide wire from the proximal end of the device to the distal end via the guide wire lumen.

[0427] Now refer to Figure 29 This is a schematic diagram of a delivery catheter according to some applications of the invention, the delivery catheter including a sheath 440 configured to facilitate reinsertion of the guideline via percutaneous puncture. Typically, the sheath includes a cover (e.g., polyurethane, polyester, silicone, polyethylene terephthalate (PET) and / or polyether block amide). A cover, which is disposed around at least a portion of the circumference of the delivery catheter 143 along a distal segment of the delivery catheter length (e.g., along a length greater than 10 mm and / or less than 100 mm, such as 10 mm–100 mm), as shown. (See reference...) Figures 28A-28E In some applications, when a ventricular assist device (VAD) is placed in a subject, it is desirable to insert another guideline via an existing percutaneous puncture, rather than retracting the VAD and subsequently having to reinsert the guideline via a percutaneous puncture. In some applications, the VAD and delivery catheter are retracted until the proximal end of the sheath 440 has been retracted from the percutaneous puncture. The guideline is then inserted through the existing percutaneous puncture by advancing it through the sheath 440 (i.e., between the cover and the outer surface of the delivery catheter 143). The VAD and delivery catheter can then be removed from this percutaneous puncture, leaving the guideline in place. In some applications, the sheath 440 is positioned around a portion of the outer tube 142 along a distal segment of the outer tube length, and the sheath functions substantially as described above.

[0428] The scope of the invention includes the use of sheath 440 on any type of percutaneous catheter to facilitate reinsertion of the guide via an existing percutaneous puncture, and is not limited to use with the delivery catheter 143 of the ventricular assist device 20.

[0429] Now refer to Figure 30 and Figure 31 These figures are schematic diagrams of a ventricular assist device 20 comprising two impellers 50 according to some applications of the present invention. Figure 30As shown, for some applications, the first and second impellers are arranged parallel to each other, each impeller being driven by its respective drive cable 130. Typically, the first impeller and its corresponding frame 34 in impeller 50 are positioned distal to the second impeller and its corresponding frame 34 in impeller 50, such that when the impellers and frames are arranged in a radially constrained configuration within the delivery catheter 143, they are not in an overlapping configuration. For some applications, the proximal impeller pumps blood via a parallel tube 24A parallel to tube 24, wherein fluid flow from the parallel tube 24A flows into tube 24 at a location configured downstream of the aortic valve 26 (the location of the aortic valve 26 is...). Figure 30 (Illustrated schematically). Therefore, typically only tube 24 (and not parallel tube 24A) passes through the aortic valve.

[0430] like Figure 31 As shown, for some applications, the first and second impellers are arranged in series, each driven by a single drive cable 130. Typically, the first impeller and its corresponding frame 34 in impeller 50 are positioned distal to the second impeller and its corresponding frame 34 in impeller 50, such that when the impellers and frames are arranged in a radially constrained configuration within the delivery conduit 143, they are not in an overlapping configuration. More typically, the impellers pump blood into the corresponding blood inlet opening 108, and initially one impeller pumps blood through tube 24, while the second impeller pumps blood through a parallel tube 24A of tube 24. Typically, fluid flow from the parallel tube 24A flows into tube 24 at a location configured downstream of the aortic valve (the location of the aortic valve is...). Figure 30 (Illustrated schematically). Therefore, typically only tube 24 (and not parallel tube 24A) passes through the aortic valve.

[0431] Note that by having one impeller pump blood through parallel tube 24A while a second impeller pumps blood through tube 24, this is not the case where the proximal impeller pumps blood that has already been pumped by the distal impeller. The inventors have found that if the proximal impeller is used to pump blood that has already been pumped by the distal impeller, this may result in inefficient pumping of blood by the proximal impeller. It should also be noted that, assuming all other things being equal, doubling the number of impellers typically doubles the amount of hemolysis produced by the ventricular assist device 20. Conversely, increasing the rotational speed of a single impeller and / or increasing the length of the impeller may result in a disproportionate increase in the amount of hemolysis produced by the impeller.

[0432] Regarding references Figures 1A-31 All aspects of the described ventricular assist device 20 should be noted, although Figure 1A and Figure 1BA ventricular assist device 20 is shown in the left ventricle of a subject; however, for some applications, device 20 is placed in the right ventricle of the subject, such that the device (with necessary modifications) passes through the subject's pulmonary valve, and the techniques described herein are applied. For some applications, components of device 20 are adapted to different types of blood pumps. For example, aspects of the invention can be applied to pumps used to pump blood from the vena cava and / or right atrium into the right ventricle, from the vena cava and / or right atrium into the pulmonary artery, and / or from the renal vein into the vena cava. These aspects may include features of tube 24 (e.g., tube curvature), impeller 50, features of pump portion 27, drive cable 130, instruments and methods for measuring blood pressure, etc. Alternatively or additionally, device 20 and / or a portion thereof (e.g., impeller 50, even without tube 24) may be placed within different parts of the subject's body to assist in pumping blood from those parts. For example, device 20 and / or a portion thereof (e.g., impeller 50, even without tube 24) may be placed in a blood vessel and may be used to pump blood through the blood vessel. For some applications, device 20 and / or a portion thereof (e.g., impeller 50, even without tube 24) (with necessary modifications) are configured for placement within the subclavian or jugular vein, at the junction of the vein and lymphatic vessels, and for increasing the flow rate of lymphatic fluid from the lymphatic vessels into the vein. Because the scope of the invention includes the use of the instruments and methods described herein in anatomical locations other than the left ventricle and aorta, ventricular assist devices and / or portions thereof are sometimes referred to herein (in the specification and claims) as blood pumps.

[0433] The following reference Figures 32A-33 The description includes components of the ventricular assist device 20, but provides some examples of devices for different anatomical locations.

[0434] Now refer to Figure 32A , Figure 32B , Figure 32C , Figure 32D and Figure 32E These figures are schematic diagrams of a cardiac assist device 360 ​​according to some applications of the present invention, which is configured to assist the function of the right heart of a subject. For components of the device 360 ​​that are substantially similar to those described above with reference to the ventricular assist device 20, the same reference numerals as used above are used. Typically, these components are substantially as described above, except for the differences described below.

[0435] Figure 32EThe device 360 ​​in a non-radial constraint configuration is shown without the subject's anatomy. As shown, typically, to assist right ventricular function in the subject, impeller 50 and frame 34 are positioned proximally at tube 24. Similarly, multiple blood inlet openings are positioned proximally at tube 24. The impeller is configured to pump blood distally through tube 24 to blood outlet opening 109 positioned distally at tube 24. For some applications, balloon 362 is positioned distally at the device. Balloon 362 is configured to facilitate the distal introduction of the device into pulmonary artery 364 by means of the balloon migrating into the pulmonary artery with the subject's blood flow. Typically, multiple blood outlet openings are configured within the pulmonary artery, such that the impeller pumps blood into the pulmonary artery via tube 24.

[0436] like Figure 32A As shown, for some applications, multiple blood inlet openings 108 are provided within the right ventricle 366 of the subject, such that an impeller pumps blood from the right ventricle through tube 24 into the pulmonary artery 364. Alternatively, multiple blood inlet openings 108 are provided within the right atrium 368 of the subject, such that an impeller pumps blood from the right atrium through tube 24 into the pulmonary artery 364, as... Figure 32B As shown. Alternatively, multiple blood inlet openings 108 are provided within the subject's superior vena cava 370, such that an impeller pumps blood from the superior vena cava through tube 24 into the pulmonary artery 364, as... Figure 32C As shown. Alternatively, multiple blood inlet openings 108 are provided within the subject's inferior vena cava 372, such that an impeller pumps blood from the inferior vena cava through tube 24 into the pulmonary artery 364, as... Figure 32D As shown.

[0437] Note that in Figures 32B-32D In the configuration shown, the cardiac assist device will reduce preload on the right ventricle (by pumping blood from the right atrium or vena cava), but will increase afterload (due to pumping blood into the pulmonary artery). In contrast, in Figure 32A In the configuration shown, the cardiac assist device effectively does not increase afterload because the volume of blood pumped into the pulmonary artery by the impeller is the same as the volume of blood pumped out of the right ventricle.

[0438] Now refer to Figure 33 This is a schematic diagram of a venous support system 380 according to some applications of the present invention. For components of the device 380 that are generally similar to those described above with reference to the ventricular assist device 20, the same reference numerals as used above are used. Typically, these components are generally as described above, except for the differences described below. For some applications, the venous support device 380 includes an impeller 50 and a frame 34, which are generally as described above. For some applications, the venous support device does not include the tube 24, for example, as... Figure 33As shown.

[0439] In some applications, the venous assist device 380 is inserted into a vein of the subject to assist in the pumping of blood through the vein. For example, the venous assist device may be inserted into a vein 382 (e.g., the iliac vein or femoral vein) in the leg of a subject whose leg is experiencing ischemia, and may assist in the pumping of blood through the vein.

[0440] For some applications, the scope of this application includes any of the following instruments and methods in combination with any other instruments and methods described herein:

[0441] One method includes:

[0442] The rigid tube is connected to the drive cable, which consists of multiple coiled wires, in the following manner:

[0443] Place the end of the drive cable and the end of the rigid tube at the given positions inside the butt-welding outer sleeve.

[0444] When the ends of the drive cable and the rigid tube are positioned at a given location within the welding sleeve, these ends are visible through a window defined by the welding sleeve, and the drive cable is placed within the welding sleeve such that a helical groove defined by a portion of the welding sleeve is positioned over the drive cable; and

[0445] A welding ring is formed around the butt-welding outer sleeve.

[0446] For some applications, forming a weld ring around the butt-welding outer sleeve includes: forming a weld ring separated from the edge of the butt-welding outer sleeve, such that the weld ring welds the butt-welding outer sleeve to the rigid tube and the drive cable, without directly welding the weld ring to the outer surface of the rigid tube and the outer surface of the drive cable. For some applications, forming a weld ring around the butt-welding outer sleeve includes: forming a weld ring to a depth such that the butt-welding outer sleeve is welded to the rigid tube and the drive cable without reducing the diameter of the inner cavity defined by the rigid tube and the drive cable. For some applications, forming a weld ring around the butt-welding outer sleeve includes: forming at least one weld ring at a given location within the butt-welding outer sleeve where the end of the drive cable and the end of the rigid tube are positioned. For some applications, coupling the drive cable to the rigid tube includes: coupling the drive cable to an axial shaft configured to support an impeller. For some applications, coupling the drive cable to the rigid tube includes: coupling the drive cable to a pin configured to couple to a magnet configured to be driven to rotate by a motor. (Refer to the above) Figures 10D-10E Some examples of this application are described.

[0447] An apparatus comprising:

[0448] The drive cable comprises multiple coiled wires;

[0449] Rigid tubes, configured to connect to drive cables; and

[0450] A butt-welding outer sleeve, configured to facilitate butt-welding of drive cables to a rigid conduit, is defined as follows:

[0451] A window, configured to provide visibility of the ends of the drive cable and the rigid tube when positioned at a given location within the weld neck sleeve, thereby facilitating the placement of the ends of the drive cable and the rigid tube at a given location within the weld neck sleeve; and

[0452] A spiral groove, located within a portion of the butt-welding outer sleeve, is configured to be positioned above the drive cable and to provide flexibility to the portion of the butt-welding outer sleeve configured to be positioned above the drive cable.

[0453] For some applications, the device includes an impeller, and the rigid tube includes an axial shaft configured to support the impeller. For some applications, the device includes a motor and a magnet configured to be driven to rotate by the motor, and the rigid tube includes a pin configured to couple to the magnet. (See above for reference.) Figures 10D-10E Some examples of this application are described.

[0454] One method includes:

[0455] The first and second parts of the drive cable, which consists of multiple coiled wires, are connected to each other in the following manner:

[0456] Place the ends of the first and second portions of the drive cable at the given positions inside the welding sleeve.

[0457] When the ends of the first and second portions of the drive cable are positioned at given locations within the welding sleeve, these ends are visible through a window defined by the welding sleeve, and

[0458] At least one portion of these parts of the drive cable is placed inside the welding sleeve, such that a spiral groove defined by a portion of the welding sleeve is disposed over at least one portion of these parts of the drive cable; and

[0459] A welding ring is formed around the butt-welding outer sleeve.

[0460] Referenced above Figures 10D-10E Some examples of this application are described.

[0461] One method includes:

[0462] The rigid tube is connected to the drive cable, which consists of multiple coiled wires, in the following manner:

[0463] Place the end of the drive cable and the end of the rigid tube at the given positions inside the butt-welding outer sleeve.

[0464] When the ends of the drive cable and the rigid tube are positioned at a given location within the welding sleeve, these ends are visible through a window defined by the welding sleeve and form welding rings around the welding sleeve. These welding rings are separated from the edge of the welding sleeve such that the welding rings weld the welding sleeve to the rigid tube and the drive cable, rather than directly to the outer surface of the rigid tube and the outer surface of the drive cable.

[0465] For some applications, forming a weld ring around a butt-welding outer sleeve includes: forming the weld ring to a depth such that the butt-welding outer sleeve is welded to the rigid tube and the drive cable without reducing the diameter of the inner cavity defined by the rigid tube and the drive cable. For some applications, forming a weld ring around a butt-welding outer sleeve includes: forming at least one weld ring at a given location within the butt-welding outer sleeve where the end of the drive cable and the end of the rigid tube are positioned. For some applications, positioning the end of the drive cable and the end of the rigid tube at a given location within the butt-welding outer sleeve includes: placing the drive cable within the butt-welding outer sleeve such that a helical groove defined by a portion of the butt-welding outer sleeve is disposed on the drive cable. For some applications, coupling the drive cable to the rigid tube includes: coupling the drive cable to an axial shaft configured to support an impeller. For some applications, coupling the drive cable to the rigid tube includes: coupling the drive cable to a pin configured to couple to a magnet configured to be driven to rotate by a motor. (Refer to the above) Figures 10D-10E Some examples of this application are described.

[0466] An apparatus comprising:

[0467] A blood pump, configured to be placed inside a subject, comprises:

[0468] impeller;

[0469] The frame is configured to be arranged around the impeller;

[0470] An axial shaft is mounted on which the impeller is installed;

[0471] Proximal radial support and distal radial support are configured to radially stabilize the axial shaft during impeller rotation;

[0472] The distal tip portion of the anti-trauma device, disposed distally relative to the impeller, includes an expandable portion; and

[0473] A cleaning fluid is configured to be pumped toward the distal tip portion in order to (a) clean the distal support and (b) expand the expandable portion of the distal tip portion.

[0474] Referenced above Figure 13D Some examples of this application are described.

[0475] An apparatus comprising:

[0476] A blood pump, configured to be placed inside a subject, comprises:

[0477] A tube that defines at least one blood inlet opening and at least one blood outlet opening;

[0478] An impeller is configured to pump the subject's blood into a blood inlet opening, through a tube, and out of a blood outlet opening;

[0479] The distal tip portion, which is disposed distally relative to the blood inlet opening, defines a radially converging shape and is configured to be placed in the left ventricle of the subject as the impeller pumps the subject's blood.

[0480] An expandable portion, disposed around the distal tip portion, is configured to define:

[0481] a) Shrinking state: When the expandable portion is in its shrinking state, the distal tip portion is configured to act as a dilator during insertion of the blood pump via a puncture into the subject's skin.

[0482] b) A first inflatable state, wherein the inflatable portion is configured to prevent damage to the subject's vascular system by the distal tip portion during its advancement through the subject's vascular system, and

[0483] c) A second expansion state in which the expandable portion expands more fully than in the first expansion state, wherein when the distal tip portion is positioned in the left ventricle of the subject, the expandable portion in its second expansion state is configured to three-dimensionally separate one or more blood inlet openings from the internal structure of the subject's left ventricle.

[0484] Referenced above Figures 20A-20C Some examples of this application are described.

[0485] An apparatus comprising:

[0486] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0487] The tube is configured such that the proximal portion of the tube passes through the subject's aortic valve, and the distal portion of the tube is positioned in the subject's left ventricle.

[0488] A frame, disposed within the distal portion of the tube, is configured to hold the distal portion of the tube in the open position.

[0489] The frame is not placed within the proximal portion of the tube, and the proximal portion of the tube is therefore configured to collapse inward in response to pressure outside the proximal portion of the tube exceeding pressure inside the proximal portion of the tube.

[0490] A pump, which is housed within a frame and configured to pump blood from the subject's left ventricle to the subject's aorta via a tube, such that during the pumping of blood through the tube:

[0491] The proximal portion of the tube remains open, and

[0492] At least a portion of the tube becomes bent, causing the tube to bend away from the posterior wall of the left ventricle.

[0493] In some applications, the pump is configured to pump blood from the subject's left ventricle to the subject's aorta through a tube, such that during the pumping of blood through the tube, at least a portion of the tube becomes bent, causing the tube to bend away from the diaphragmatic wall of the left ventricle. (See above for reference.) Figures 25A-25F Some examples of this application are described.

[0494] An apparatus comprising:

[0495] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0496] The tube is configured such that the proximal portion of the tube passes through the subject's aortic valve, and the distal portion of the tube is positioned in the subject's left ventricle.

[0497] A frame, disposed within the distal portion of the tube, is configured to hold the distal portion of the tube in the open position.

[0498] The frame is not placed within the proximal portion of the tube, and the proximal portion of the tube is therefore configured to collapse inward in response to pressure outside the proximal portion of the tube exceeding pressure inside the proximal portion of the tube.

[0499] A pump, which is housed within a frame, is configured to pump blood from the subject's left ventricle to the subject's aorta via a tube, such that the proximal portion of the tube remains open during the pumping of blood through the tube.

[0500] as well as

[0501] A bending element, which is disposed proximally within the tube relative to the frame, is configured to bend at least a portion of the tube away from the posterior wall of the left ventricle.

[0502] In some applications, the bending element is configured to bend at least a portion of the tube, causing the tube to bend away from the diaphragmatic wall of the left ventricle. (See above for reference.) Figures 25A-25FSome examples of this application are described.

[0503] An apparatus comprising:

[0504] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0505] The tube is configured such that the proximal portion of the tube passes through the subject's aortic valve, and the distal portion of the tube is positioned in the subject's left ventricle.

[0506] The frame, which is disposed within at least the distal portion of the tube,

[0507] A pump, which is disposed within a frame and configured to pump blood from the subject's left ventricle to the subject's aorta via a tube, wherein blood is pumped into the tube through a set of one or more blood inlet openings defined by the tube and disposed within the subject's left ventricle, and blood is pumped out of the tube through a set of one or more blood outlet openings defined by the tube and disposed within the subject's aorta.

[0508] At least one of the openings in the tube is configured in a non-axisymmetric configuration relative to the tube, such that pumping blood through at least one of the openings causes at least a portion of the tube to bend, causing the tube to bend away from the posterior wall of the left ventricle.

[0509] In some applications, at least one of the openings in the tube is configured in a non-axisymmetric manner relative to the tube, such that pumping blood through at least one of these openings causes at least a portion of the tube to bend, causing the tube to bend away from the diaphragmatic wall of the left ventricle. (See above for reference.) Figures 25A-25F Some examples of this application are described.

[0510] An apparatus comprising:

[0511] Impeller, the impeller comprising:

[0512] An impeller frame comprising a proximal portion and a distal portion, and at least one helical elongated element wound from the proximal portion to the distal portion;

[0513] Material, which is coupled to at least one helical elongated element, such that the at least one helical elongated element coupled with the material defines the blades of an impeller; and

[0514] A coil wound around at least one helical elongated element, the coil being configured to facilitate the attachment of material to at least one helical elongated element.

[0515] One method includes:

[0516] The impeller is manufactured as follows:

[0517] A structure is formed having a first end portion and a second end portion at the proximal and distal ends of the structure, and these end portions are connected to each other by at least one elongated element.

[0518] A coil is wound around at least one elongated element;

[0519] By axially compressing the structure, at least one elongated element is radially expanded and forms at least one helical elongated element; and

[0520] The material is attached to at least one helical elongated element such that the at least one helical elongated element with the attached material defines the blades of the impeller.

[0521] The coil is configured to facilitate the connection of the material with the helical elongated element.

[0522] Referenced above Figures 3A-3K Some examples of this application are described.

[0523] An apparatus comprising:

[0524] Impeller, the impeller comprising:

[0525] An impeller frame comprising a proximal portion and a distal portion, and at least one helical elongated element wound from the proximal portion to the distal portion;

[0526] Material, which is coupled to at least one helical elongated element, such that the at least one helical elongated element coupled with the material defines the blades of an impeller; and

[0527] A sleeve, which is arranged around at least one helical elongated element, is configured to facilitate the attachment of material to at least one helical elongated element.

[0528] One method includes:

[0529] The impeller is manufactured as follows:

[0530] A structure is formed having a first end portion and a second end portion at the proximal and distal ends of the structure, and these end portions are connected to each other by at least one elongated element.

[0531] A sleeve is placed around at least one elongated element;

[0532] By axially compressing the structure, at least one elongated element is radially expanded and forms at least one helical elongated element; and

[0533] The material is attached to at least one helical elongated element such that the at least one helical elongated element with the attached material defines the blades of the impeller.

[0534] The sleeve is configured to facilitate the connection of material with the helical elongated element.

[0535] Referenced above Figures 3A-3K Some examples of this application are described.

[0536] An apparatus comprising:

[0537] Impeller, the impeller comprising:

[0538] An impeller frame comprising a proximal portion and a distal portion, and at least one helical elongated element wound from the proximal portion to the distal portion, the helical elongated element having a rounded cross-section; and

[0539] A material, which is coupled to at least one helical elongated element, such that the at least one helical elongated element to which the material is coupled defines the blades of an impeller; and

[0540] The roundness of the spiral elongated element is configured such that the material forms a layer of substantially uniform thickness at the interface between the material and the spiral elongated element.

[0541] One method includes:

[0542] The impeller is manufactured as follows:

[0543] A structure is formed having a first end portion and a second end portion at the proximal and distal ends of the structure, the end portions being connected to each other by at least one elongated element having a rounded cross section;

[0544] By axially compressing the structure, at least one elongated element is radially expanded and forms at least one helical elongated element; and

[0545] The material is attached to at least one helical elongated element such that the at least one helical elongated element to which the material is attached defines the blades of the impeller.

[0546] The roundness of the spiral elongated element is configured such that the material forms a layer of substantially uniform thickness at the interface between the material and the spiral elongated element.

[0547] Referenced above Figures 3A-3K Some examples of this application are described.

[0548] One method includes:

[0549] The impeller is manufactured as follows:

[0550] A structure is formed having a first end portion and a second end portion at the proximal and distal ends of the structure, and these end portions are connected to each other by at least one elongated element.

[0551] By axially compressing the structure, at least one elongated element is radially expanded and forms at least one helical elongated element;

[0552] The first end of the annular elongated element is made to loop around the spiral elongated element, the annular elongated element having a predetermined length and being substantially non-stretchable;

[0553] A spring is inserted along an axis defined by a first end portion and a second end portion, such that the second end of the annular elongated element forms a loop around the spring;

[0554] The material is coupled to at least one helical elongated element and a spring, such that a membrane of the material is supported between the helical elongated element and the spring, and the membrane of the material defines the blades of the impeller.

[0555] The annular elongated element is configured to hold the helical elongated element within a given distance from the spring.

[0556] Referenced above Figures 3A-3K Some examples of this application are described.

[0557] An apparatus comprising:

[0558] A left ventricular blood pump, comprising:

[0559] impeller;

[0560] A motor configured to drive an impeller to pump blood from the subject's left ventricle to the subject's aorta by rotating the impeller; and

[0561] A computer processor is configured to measure the motor power required to rotate the impeller at a given rotational rate, and to determine the subject's left ventricular blood pressure in at least part of that response.

[0562] Referenced above Figure 9 Some examples of this application are described.

[0563] An apparatus comprising:

[0564] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0565] A blood pump tubing is configured such that a proximal portion of the tubing passes through the aortic valve of a subject, and a distal portion of the tubing is disposed in the left ventricle of the subject. The tubing defines at least one blood inlet opening and at least one blood outlet opening, the at least one blood inlet opening being disposed in the left ventricle and the at least one blood outlet opening being disposed in the aorta of the subject.

[0566] An impeller is configured to pump blood from the left ventricle of a subject to the aorta through a tube, by means of pumping blood into the tube through one or more blood inlet openings defined by the tube and disposed within the left ventricle of the subject, and pumping blood out of the tube through one or more blood outlet openings defined by the tube and disposed within the aorta of the subject.

[0567] A drive cable, configured to extend from the impeller to the outside of the subject;

[0568] One or more outer tubes, with drive cables configured to rotate within the outer tubes;

[0569] A motor, which is disposed outside the subject and configured to drive an impeller to rotate via a drive cable; and

[0570] A stator configured to reduce the rotational flow component of blood flow through the blood pump tube before blood flows out from at least one outlet opening, the stator comprising:

[0571] The frame, which is connected to one or more outer tubes within the blood pump tubing; and

[0572] A flexible material is attached to the frame such that, in a non-radial constrained configuration of the stator, the stator defines a plurality of curved protrusions extending radially from one or more outer tubes.

[0573] For some applications, the framework is a self-expanding framework. (See above for reference.) Figures 14A-14C Some examples of this application are described.

[0574] An apparatus comprising:

[0575] A left ventricular assist device configured to assist left ventricular function in a subject, the left ventricular assist device comprising:

[0576] A blood pump tubing is configured such that a proximal portion of the tubing passes through the aortic valve of a subject, and a distal portion of the tubing is disposed in the left ventricle of the subject. The tubing defines at least one blood inlet opening and at least one blood outlet opening, the at least one blood inlet opening being disposed in the left ventricle and the at least one blood outlet opening being disposed in the aorta of the subject.

[0577] An impeller is configured to pump blood from the left ventricle of a subject to the aorta through a tube, by means of pumping blood into the tube through one or more blood inlet openings defined by the tube and disposed within the left ventricle of the subject, and pumping blood out of the tube through one or more blood outlet openings defined by the tube and disposed within the aorta of the subject.

[0578] The blood pump tube defines a stator configured to reduce the rotational flow component of the blood flow through the blood pump tube before the blood flows out from at least one outlet opening.

[0579] For some applications, the stator includes one or more curved strips within the blood pump tube. For some applications, the stator includes multiple strips disposed within the blood pump tube to divide the blood pump tube into multiple compartments. For some applications, the stator includes a portion of the blood pump tube comprising multiple helical tubes. For some applications, the stator includes a portion of the blood pump tube that is twisted such that the tube wall defines folds, thereby reducing the rotational flow component of the blood flow through the blood pump tube before blood flows out from at least one outlet opening. (Refer to the above text) Figures 15A-15E Some examples of this application are described.

[0580] An apparatus comprising:

[0581] A blood pump, configured to be placed inside a subject, comprises:

[0582] The impeller includes a proximal bushing and a distal bushing;

[0583] The frame is configured to be arranged around the impeller;

[0584] The proximal radial support and the distal radial support are respectively located at the proximal end and the distal end of the frame;

[0585] An axial shaft is configured to pass through the proximal and distal radial supports, as well as the proximal and distal bushings of the impeller.

[0586] The distal bushing of the impeller is connected to the axial shaft, such that the distal bushing is held in a fixed axial position relative to the axial shaft.

[0587] The proximal bushing of the impeller is not connected to the axial sha...

Claims

1. An apparatus comprising: Blood pump, the blood pump comprising: - An impeller, configured to pump blood through the subject's body; - A frame arranged around the impeller, wherein, in a radially unconstrained configuration of the frame, the frame defines a proximal conical portion and a cylindrical portion disposed distal to the proximal conical portion. During at least partial operation of the blood pump, at least a first portion of the impeller is disposed within the proximal conical portion of the frame, and during at least partial operation of the blood pump, at least a second portion of the impeller is disposed within the cylindrical portion of the frame. The impeller includes at least a portion along which the diameter of the impeller increases toward the position of maximum span of the impeller, and wherein, during at least a portion of operation of the blood pump, the diameter of the impeller along the increasing portion is disposed within the proximal conical portion of the frame.

2. The device according to claim 1, wherein, The frame further defines a distal tapered portion disposed on the distal side of the cylindrical portion.

3. The device according to claim 1, wherein, Throughout the operation of the blood pump, at the position where the impeller span is at its maximum, the impeller is configured to be located within the cylindrical portion of the frame.

4. The device according to claim 1, wherein, The frame includes pillars shaped to define cells, wherein the density of the pillars increases from the proximal tapered portion toward the cylindrical portion.

5. The device according to claim 4, wherein, The frame also defines a distal tapered portion disposed on the distal side of the cylindrical portion, wherein the density of the struts increases from the distal tapered portion toward the cylindrical portion.

6. The apparatus according to claim 4, wherein, Within the columnar portion of the frame, the support density of the frame is constant.

7. The device according to claim 4, wherein, The width of each cell within the cylindrical section, measured around the circumference of the cylindrical section, is less than 2 mm.

8. The apparatus according to claim 7, wherein, The width of each cell within the cylindrical section, measured around the circumference of the cylindrical section, is between 1.4 mm and 1.6 mm.

9. The apparatus according to claim 7, wherein, The width of each cell within the cylindrical section, measured around the circumference of the cylindrical section, is between 1.6 mm and 1.8 mm.

Images